They are doing a good job of making their new mechanics work, especially if they look really cool on the surface.
Weaknesses: Can be removed by retreating, evolving, or using Trainer cards
Worldly Tutor and Fierce Empath help you search for it from your deck
If your opponent loses the game after you declare attackers but before the melee trigger itself resolves (say, they were already at 3 life and someone Lightning Bolts them), the melee buff will still count that opponent as someone youve attacked this combat. What does matter is that you have to declare the attack for it to count towards the melee buff
If you want to build a variation on Party Time with Tazri, I'd have you drop out the underperforming, overcosted cards that play better in sealed and draft and add in more removal and a few boardwipes
It can come down on its own in the late game and take over a board state, creating an army of squirrels outright or turning an existing army into finishers