There are a few rules for Commander Cube that arent present in traditional EDH: Mono-colored commanders can splash one color
You already know how good that can be
Brawl Not Legal Vintage Legal Timeless Not Legal Commander Legal Pauper Not Legal Oathbreaker Legal Penny Not Legal Toolbox Notes and Rules Information for Sin, Unending Cataclysm: Sin's last ability puts all counters that were on Sin onto the target creature, not just its +1/+1 counters
Drawing good comparisons to Goblin Rabblemaster, Howlsquad Heavy combines giving haste to your creatures and making a token every turn
That said, this is still just a hard-to-cast Thoughtseize, which is going to miss often enough that it might not be worth playing
Like most of the other Toy cards, she works best with Toy synergy, allowing you to draw a card if there are two other Toys in play