She is runnable as a Commander and nasty as a bull running if you do, but she's way too powerful, so skip her as the leader
PS: maybe an idea for finding the missing cards: compare the LQ images downloaded by Forge with your images (comparing the same directories like "4E", "5E", ...)
Damage counters totalling 20 HP will be added to the Wishiwashi
Mangara, the Diplomat is a decent 2/4 blocker with Lifelink so its not so easily killed with burn spells or by combat damage
But Hardened Scales could use a bit of a boost, and I dont think anyone would mind if that deck had some more front end power
Token generators that produce creatures are a good way to combat removal since you can flood the board with targets, and make the removal spell feel like a waste