I noticed one of the blue building requirements is to "Have at least 1 pet with an overall rating of 100 or more". What is that? And how do I get there? I've never been exactly quite sure. XD Thanks for any help, I really appreciate it.

I think you just need them to add up to 100 for one pet, seeing as I was able to get into the Blue Building with not one stat at 100.

it's strength + defense + health + speed = 100.