Hey Zorua! PlatinumDude mentioned OU, but I want to propose something else to you: Change up a little bit for it to be viable in NeverUsed. :) It's harder to get battles but certainly a lot of fun if you get a chance! These Pokemon are mostly in NU and they can be somewhat useful there, so if you're interested I'll provide a rate more relevant to NU, in case you don't want to have to replace everything.
Seismitoad has to change up a bit. It has great special attack, and no waterfall, so it's better off with Surf so you can abuse the special attacking side. Unfortunately it has the worst possible ability for a Seismitoad! But you can always re-breed it, given that it's been EV'd in the wrong things anyway :x If you give it something like Rain Dance, Sludge Wave, Earth power, and Surf, then you have coverage over almost everything common in NeverUsed, can put rain up, can boost your speed if you grab Swift Swim as the ability (and EV in special attack/speed), and allow Ampharos to abuse Thunder! In terms of Espeon, you want a stalling Pokemon, yeah, Musharna is a better fit given that it has great bulk and Espeon isn't really EV'd right to Toxic stall, sadly. Plus Espeon is OU, and Musharna is NU, which is what the majority of your team is in. You could give Musharna something fun like Thunder Wave/Heal Bell/Psychic/Moonlight and you can make it into a "cleric" (something which can support your team basically, through a variety of ways like healing status etc) and stop strong physical attackers. Ampharos isn't really the greatest but since you want a specially attacking one, instead of going all electric (which means you can't touch ground sadly!) you could go Thunder (thanks to Seismitoad having Rain Dance), Focus Blast, Hidden Power Ice, and Thunderbolt if you'd like. Crobat is interesting, there's nothing really in NU that fits its role, however, there is a fun Pokemon you can abuse. If you have Black 2/White 2, then try to grab a Prankster Liepard - if not, you can ask for someone to trade it in PC's Quick Trade thread. This has Encore/Substitute/Swagger/Foul Play. You can confuse Pokemon with Swagger like you wanted, and when their attack goes up, Foul Play hits even harder so it's a really awesome combo! Also with Prankster it means Substitute/Encore and Swagger will always hit first, and it's fast in general too, often causing people to pull their hair out ;)
I'd continue commenting but I realise this isn't really what you want, and I'm just providing an overall analysis :(
Also, Toxic stall isn't really the most viable. There's other types of stall that fit much better (mostly being hazard stall). This means you use Stealth Rock, Spikes, Toxic Spikes (yesss you can use Toxic Spikes!!) and then Phaze the opponent away (basically, using Whirlwind or Roar) and boom, damage and Toxic Spikes build up. If you wanted to do this, you could use Pokemon like Garbodor, Roselia, and so on for Toxic Spikes/Spikes, Golem, Regirock, Seismitoad (it can SR) and so on for Stealth Rock. It just depends! But yeah, then grab something with whirlwind and roar, or dragon tail even, (to force the opponent out), something that can block rapid spin (which pretty much spins away your hazards, which are stealth rock, etc) - which is a ghost pretty much, as rapid spin is a normal attack, and you can have a fun combination! There's a lot in NU (as found here:
http://www.smogon.com/bw/tiers/nu) so you can check it out whenever you wanna.
The unfortunate thing is that a lot of Pokemon do need changing in competitive, and you should possibly plan out your team on a battling simulator before you actually EV everything, so make sure you're okay. :) It's great that you're starting out competitive battling though, and while the terminology and everything may be confusing, it's easy once you've played for a while! Feel free to check over Battle Center's guides (in the main Battle Center forum) to help you out more in regards to competitive. Also, if you're confused, feel free to head to the PC Battle Server (which isn't working right now, but should in a day or two) and ask for help from any of us more experienced battlers. :3