For whatever reason, Bloomburrow has lumped in Squirrels with Rats, Insects, and Spiders, even though they're easily the least creepy critters on the list
For five mana to drop, you can spend one when your foe's draw, and then share their draw
The creature itself is a good flying threat to put onto the battlefield, but its real power comes from its ability to flicker all non-land permanents you control
Brawl has a different banned list than Standard, but currently the only banned card is Sorcerous Spyglass, which will leave Standard in October
However, Nesting Grounds does not specify creatures, so you could move counters onto any other permanent with this land
The re stock is likely just the last part of the initial printing run thats now been boxed up and shipped out