In singles, Blaziken is a terror. In doubles, not so much. The prevalence of Protect in VGC is what makes High Jump Kick risky to use in that format. Blaziken can get away without its Mega Evolution, as Life Orb Blaziken hits harder than Mega Blaziken:
-Flare Blitz
-Low Kick
-Knock Off/Stone Edge
-Protect
Nature: Adamant
EVs: 252 Atk/4 Def/252 Spe
Item: Life Orb
Ability: Speed Boost
Dragon Pulse and Ice Beam are redundant on Milotic. It's a pretty good abuser of Competitive in doubles formats because Intimidate is an uncommon ability:
-Scald
-Ice Beam/Icy Wind
-Recover/Icy Wind
-Protect/Mirror Coat
Nature: Modest
EVs: 236 HP/140 Def/132 SAtk
Item: Leftovers/Sitrus Berry/Assault Vest
Ability: Competitive
Manectric is better off with its Mega Stone. It's mediocre without it:
-Thunderbolt/Volt Switch
-Overheat/Flamethrower
-Hidden Power (Ice)/Volt Switch/Snarl
-Protect
Nature: Timid
EVs: 4 Def/252 SAtk/252 Spe
Item: Manectite
Ability: Lightning Rod
All Pokemon in the National Dex are legible for this VGC format. Even if this may breach what you intend, there are better Grass Pokemon more suitable for doubles than Cradily. Amoonguss is one prime example, as it has Rage Powder to redirect unwanted attacks:
-Spore
-Rage Powder
-Giga Drain/Sludge Bomb
-Protect
Nature: Relaxed
EVs: 252 HP/252 Def/4 SDef
Item: Sitrus Berry/Rocky Helmet
Ability: Regenerator
In VGC formats, regular Salamence is better off using special attacks, as burn and Intimidate tend to render physical variants useless:
-Draco Meteor
-Dragon Pulse
-Fire Blast
-Stone Edge/Rock Slide/Hydro Pump
Nature: Timid/Modest
EVs: 4 Def/252 SAtk/252 Spe
Item: Choice Scarf
Ability: Intimidate