[@Holy Grail] 
If you want, you could ask just to be sure, although most of us would be alright with you using some of our species. As for a sub-species, that seems fine with me. 

Although I've thought of something, a sort of loophole if you really want your own species. Some of our Garden Worlds do not have a full species roster, two with just two(Erelvath and Terra) and another with only one(Joord), although technically they no longer are on said planet, chased away by their creations, the Schäferkin. So if either of the three players of the garden worlds are willing, maybe you can construct a history of a missing race or two that fled these worlds enmass for whatever reason.