I have no problem with introducing other animal's DNA appearing througout the RP, but in the very beginning I personally think it'd be best to stick to the simpliest route to get the players up to speed and interested - like how in FF7 you start out with a mission to blow up the reactor and only know that you're doing it for the secret organization called Avalanche. ALL great fantasy novels - with the exception of LOTR - began with action and then hit the main plot with intense story.
I feel that making the beginning to complex and disorganized with more than the usual DNa animals, then the others will only get confuzed and post less and less. For the beginning I'd say only cats, dogs, monkeys, and birds should be KNOWN to be tested on, but with hints that there were many others creatures tested on and we will find out what those are as the story progresses.
My question, though, is "What is our starting point?" If we're confused from the start, without being together or knowing what to do, than this one won't last too long. So Leader, what is our starting point and goal in the very beginning?