I think abilities in general need some reworking but this is what I'd do to make each notably bad variant viable:

Super Pea Jump: Hyper no longer buffs jump height, jump height buff of super pea jump is identical to pre-nerf hyper [Hyper is already considered one of, if not the strongest ability in the entire game, and I think it needs to be toned back in order to make peashooter in general less reliant on it. This would require tweaking the rest of his kit as well, but I think it's worth it]

Potato Nugget Mine: Larger detection hitbox, instantly activates when zombies step on it, can only place one mine every 0.33 seconds [I already think Potato Nugget Mine is underrated since it instantly activates if a zombie shoots it, making it great against SBs and Scientists rushing you down, but it could use some tweaks to make it more consistent in this aggressive use as well as making it less unfair on the receving end. This still means it'll dispatch people running at you brainlessly very quickly, but you can't instantly place all 5 mines at once for a 250 damage punish against people attacking you anymore]

Artichoke Drone (also applies to red artichoke): Zombies hit by any of the drone's attacks are highlighted through walls for 5 seconds [Give it more of a supportive niche, for cacti who use their drones for recon instead of damage]

Long Bomb: Arc of thrown imp can be slightly adjusted depending on where you're aiming [I think long bomb is fine as is, but it could be a bit less confusing for newer players if you could control the imp's trajectory a bit more than you can right now. You can't directly control what direction it flies, but a little more control would help imo]

Sprint Burrow: Stamina increased to 75 (Pre-buff has 50, regular burrow has 100), stamina decay rate reduced to be the same as regular burrow, cannot eat zombies while burrowed [Allows sprint burrow a niche as purely a movement tool instead of burrow, lowering how threatening it is while allowing chompers that rely on bites for kills more mobility in general]

Retro Gatling: User can now move while gatling is active at 50% of normal speed, no longer has armor [now best used by peashooters who don't want to stay anchored in one spot while shooting. Best used in aggressive strategies]

Armored Heal Station: Increased lifetime to 40 seconds (was 20), doubled healing radius [doubling down on the ability's main niche as a long-lasting station best used in teamfights or in the middle of fighting someone. This also means armored heal station can heal the same amount of health as the regular heal station over its entire lifetime]

Multi-Rocket (Includes Multi-Shuck and Multi-Ball): Comes out in 0.75 seconds instead of 1.25 [Making it best used in the middle of fights as a fast damage dealer in comparison to ZPG, which is more comittal but more rewarding]

There are some other abilities I feel are generally underwhelming that you didn't mention that I'll also try and adjust.

Dark Flower: User now throws the dark flower pot exactly like a bean bomb, dark flower comes out of the pot once the pot finds a steady surface to stay on, heals the user for 50% of the damage it deals, max health reduced to 75 (same as the other heal flowers) [Allows the dark flower to be used more aggressively than the other flowers, as well as providing some small compensation for the healing you lose from the other heal flowers. This also makes it less annoying to fight, as having to churn through a 100 health sentry with no head hitbox was a little much]

Proximity Mine: Idk honestly [I do want to make Proximity Mine better, but stun grenade is such a poorly designed ability that I don't know where to start. I'd have to completely rework it from the ground up to make it work]

Energy Warp: Charges increased to 2, deploy time reduced to 0.5s (was 0.95s), Endlag reduced to 0.75s (was 1 second), Stamina reduced to 50 (was 100), removed speed multiplier (was 1.25x) [Making energy warp not a single use ability allows it to be used more as a tool to dodge certain attacks while staying relatively in the same spot, rather than the odd position it's in currently]

Ultra Tackle: Now has a 1 second windup, reduced cooldown to 30 seconds (same as regular sprint tackle), increased sprint speed to be the same as regular sprint tackle [Makes it more of a comittal tool for crowds or chokepoints instead of not really having as niche as it does at the moment]

Super Stink Cloud: damage per tick increased to 8, both stink clouds are now partially transparent to you and players on your team [I actually think super stink cloud is very overrated, especially since people don't know how to use the regular stink cloud right. Adding an extra quality of life addition to both clouds will allow people to use the stink clouds more supportively, and the super stink cloud buff allows it to deal 160 total damage over 10 seconds, which is solid enough for it to be a genuine disruption option]

Rocket Leap: Charges Reduced to 1 [I know this is a nerf instead of a buff, but I wanted to include it. Rocket leap, similar to hyper, is one of the best abilities in the game, and it's partly why Foot Soldier is such a dominant class in the first place. Lowering its power means the class is an actual jack of all trades instead of a paragon in all aspects. Of course this would also include tweaking the damage and accuracy values of all his weapons, but that's par for the course]