Seems like a UU team to me.
IMO, I'd rather have Florges over Umbreon so that you don't have type overlap with Absol:
-Wish
-Protect
-Moonblast
-Aromatherapy/Toxic
Nature: Calm
EVs: 252 HP/232 Def/24 SDef
Item: Leftovers
Stealth Rock is a staple in competitive play because it damages all Pokemon upon switching in; the amount of damage done depends on the Pokemon's type. Donphan is a bulky Stealth Rock setter you can turn to:
-Stealth Rock
-Earthquake
-Knock Off/Toxic/Roar
-Rapid Spin
Nature: Impish
EVs: 252 HP/252 Def/4 SDef
Item: Leftovers
Ability: Sturdy
Here's a better take on Jellicent. What purpose do the Special Attack EVs even serve in the first place? The below Speed investment allows this Jellicent to outspeed 0 Speed base 65s:
-Scald
-Will-o-Wisp
-Recover
-Taunt
Nature: Calm
EVs: 252 HP/212 SDef/44 Spe
Item: Leftovers
Ability: Water Absorb
Stockpile isn't worth it on Weezing because it makes it a critical hit magnet and setup bait alongside Swords Dance/Nasty Plot attackers (especially Mega Houndoom):
-Toxic Spikes
-Sludge Bomb/Flamethrower
-Will-o-Wisp
-Pain Split/Haze
Nature: Bold
EVs: 252 HP/252 Def/4 SDef
Item: Black Sludge
Coil is useless on Milotic because not only is its Attack terrible, but your current set lacks any physical moves to make use of the Attack boost; that, and Milotic will still be setup bait. Cute Charm is also a bad ability because it's gender-matchup-dependent, and the gender aspect of Pokemon is very random, even though some Pokemon are all-male or all-female. Marvel Scale is, and always will be, the better ability to turn to, as even though Milotic is worn down faster by burn or poison, the Defense buff will make it harder for physical attackers to break it. It would be preferable for Milotic to be paralyzed, though. The below set has Haze or Dragon Tail as options to discourage opponents from setting up on Milotic. Also, confusion is a bad status ailment to throw around, as it can be easily be cured by switching out:
-Scald
-Ice Beam
-Toxic/Haze/Dragon Tail
-Recover
Nature: Bold
EVs: 248 HP/252 Def/8 SDef
Item: Leftovers
Ability: Marvel Scale
I don't think Lilligant is worth it because while it has the threat of Sleep Powder to make setting up Quiver Dance easier, it gets easily walled by Steel Pokemon or Fire Pokemon, depending on what Hidden Power type you opt for. Since this team is about tanks, I think Chesnaught will get the nod ahead of Lilligant because of its good physical bulk and support options:
-Spikes
-Leech Seed/Synthesis
-Wood Hammer/Drain Punch
-Spiky Shield/Roar
Nature: Impish
EVs: 252 HP/252 Def/4 SDef
Item: Leftovers
Ability: Bulletproof
Relying on critical hits is an inconsistent strategy because fishing for crits doesn't pair well with (Mega) Absol's frailty. That, and Absol will lose one of its regular abilities in favor of Magic Bounce when it Mega Evolves. That being said, Stone Edge and Psycho Cut aren't useful, and Absol should make use of the buffed Knock Off to get rid of items:
-Swords Dance
-Knock Off
-Sucker Punch
-Superpower/Play Rough
Nature: Jolly
EVs: 252 Atk/4 SDef/252 Spe
Item: Absolite
Or, if you don't like the aspect of setting up, here's a mixed/all-out attacking set:
-Sucker Punch
-Knock Off
-Play Rough/Superpower
-Fire Blast/Superpower
Nature: Naive/Jolly
EVs: 252 Atk/4 SAtk/252 Spe
Item: Absolite
I assumed this is a UU team, given that the vast majority of your team members are from that tier. Breloom is an OU Pokemon, so you'll have to find something else for that slot.
I don't really play using Smogon rules to be honest, i don't really know what they all mean, i basically chose this team because it uses some (i believe) decent pokemon that aren't in the overpowered area (talking base stats of 550+)
Thank you for taking the time to write out all of your suggestions, I feel i should explain a little more as to why i've done what i've done:
Coil is useless on Milotic because not only is its Attack terrible, but your current set lacks any physical moves to make use of the Attack boost; that, and Milotic will still be setup bait. Cute Charm is also a bad ability because it's gender-matchup-dependent, and the gender aspect of Pokemon is very random, even though some Pokemon are all-male or all-female. Marvel Scale is, and always will be, the better ability to turn to, as even though Milotic is worn down faster by burn or poison, the Defense buff will make it harder for physical attackers to break it. It would be preferable for Milotic to be paralyzed, though. The below set has Haze or Dragon Tail as options to discourage opponents from setting up on Milotic. Also, confusion is a bad status ailment to throw around, as it can be easily be cured by switching out:
-Scald
-Ice Beam
-Toxic/Haze/Dragon Tail
-Recover
Nature: Bold
EVs: 248 HP/252 Def/8 SDef
Item: Leftovers
Ability: Marvel Scale
With Milotic, i've gone for coil simply for the defense buff, basically it was the only move that buffs defense that Milo can learn. I use cute charm over marvel scale because i'm not a fan of my own pokemon being hindered, with burn or toxic i'm constantly worrying about if i get criticaled, will the burn or toxic finish me off, with paralysis i'd be worried about losing a turn. with Cute charm it is a little hit and miss but has 0 downside, but i used Confuse ray in there to counter any females (basically Milotic is my staller) Scald is there to burn, confuse ray is there so i can safely set up coils, or force a switch and cute charm removes physical attackers for 50% of attacks. In my opinion (i'm not saying im right) but this fits Milotic better for the way i use it as although it takes a bit of time to set up, if you get coil off a few times your benefiting from +1 to 6 defense boost which can be better than marvel as there's no hindering factor, plus you are also getting an accuracy boost (not that you need it but i suppose its nice in case someone increases evasion or lowers your accuracy). With Toxic and scald, they are two status affects that would render the other useless, if i burn i can't poison and vise versus, my team revolves around burning and ruining any physical attackers while completely walling special attackers with high Special defense.
Stockpile isn't worth it on Weezing because it makes it a critical hit magnet and setup bait alongside Swords Dance/Nasty Plot attackers (especially Mega Houndoom):
-Toxic Spikes
-Sludge Bomb/Flamethrower
-Will-o-Wisp
-Pain Split/Haze
Nature: Bold
EVs: 252 HP/252 Def/4 SDef
Item: Black Sludge
With Weezing i went stockpile to boost both defense and special defense to +3 making weezing very bulky, does stockpile increase the likely hood of receiving a crit? i chose fireblast to cover any steel pokemon that'd come in and nullify weezing as poison attacks don't affect steel well, however will swap it for flamethrower for more PP and better accuracy.
Here's a better take on Jellicent. What purpose do the Special Attack EVs even serve in the first place? The below Speed investment allows this Jellicent to outspeed 0 Speed base 65s:
-Scald
-Will-o-Wisp
-Recover
-Taunt
Nature: Calm
EVs: 252 HP/212 SDef/44 Spe
Item: Leftovers
Ability: Water Absorb
Forgive me if i'm wrong here but i figured raising Jellicents Special attack would increase damage of Hex and scald, Jelly is pretty bulky anyway so i've never worried about outspeeding (in my mind the idea of tanks are to hit hard and take hits at the cost of being slow as hell). so that was the reason for that, i found using cursed body more useful as it disabled the use of an attack, lets say they have one super effective move against you and its disabled, you'll last longer. i personally don't feel water absorb really helps as not many people are going to be using a water attack against a water pokes.
I don't think Lilligant is worth it because while it has the threat of Sleep Powder to make setting up Quiver Dance easier, it gets easily walled by Steel Pokemon or Fire Pokemon, depending on what Hidden Power type you opt for. Since this team is about tanks, I think Chesnaught will get the nod ahead of Lilligant because of its good physical bulk and support options:
-Spikes
-Leech Seed/Synthesis
-Wood Hammer/Drain Punch
-Spiky Shield/Roar
Nature: Impish
EVs: 252 HP/252 Def/4 SDef
Item: Leftovers
Ability: Bulletproof
I do like the idea of chesonaught, i will have to work on getting one and using your method for that, it could be a good substitute for Lilligant.
Relying on critical hits is an inconsistent strategy because fishing for crits doesn't pair well with (Mega) Absol's frailty. That, and Absol will lose one of its regular abilities in favor of Magic Bounce when it Mega Evolves. That being said, Stone Edge and Psycho Cut aren't useful, and Absol should make use of the buffed Knock Off to get rid of items:
-Swords Dance
-Knock Off
-Sucker Punch
-Superpower/Play Rough
Nature: Jolly
EVs: 252 Atk/4 SDef/252 Spe
Item: Absolite
I find that due to Absols god aweful defenses that it usually dies before it has chance to use an attack after a sword dance, thats why i don't use it, As i mentioned i used stone edge to take advantage of the high crit chance when absols in normal form, this gives me an element of surprise when i face flying or fire mon's however i do like the idea of knock off as i could use a mon with it to remove the opponents items. so good call on that.
As for Psycho cut, i was using it to combat any Fighting types that Absols weak too or poison, it gives a bit of coverage as Play rough is crap against poison. I don't think super power would be very useful as most mons swapping in to beat absol will have a resistance to fight (Fight, Fairy, Bug etc) plus the stat drop wouldn't be fun.
I think i will either replace Psycho-cut or stone edge with knock off as you suggested.