I mean, there necessarily isn't any reason a porcupine couldn't come in the next pack.
After all, it may tease a potential arboreal and/or social species, but not all of them will be social or climbers
Arboreal would work for most new world porcupines - brazilian (my new "get this in the game" obession) and North american come to mind
Rainforests - Several of the South American variety
Islands - The Philippine Porcupine
Kids Zoo - Crested Porcupine
Drylands - Crested/Caped/Indian Porcupine
Temperate/Woodlands - NA Porcupine
General Asia - Indian Porcupine
Tundra/Taiga - NA Porcupine (yes, they can live in the Tundra!)
Avian - they're in the air if they fall out of trees. That counts, right? RIGHT?
Alas, I don't really think this time around will be the Porcupine's moment, unless it's rainforests and arboreal, and while it would work as an oddball pick, there's too many higher profile animals to go to first, and they'll leave it out to get an Old World species in later. I think as far as the major wants go the Tasmanian Devil and Sloth have the highest chance of making it into whatever theme this pack will be.