Can it just be one animal type instead of combining species?
It can be just one type of species. Nothing is set in stone as to what will happen to your character. These are things I am leaving up to you. If, say, something were to make Dr. Patchov stop at just one mutation, he would. Some other characters are likely to get several, over time. Nothing will be all at once.
In the end, I prefer to have the victimish characters look quite similar to normal humans, very difficult to really tell between a normal human and an experimental one. I suppose if say, your character were to develope a feature that marked your character as distinctly inhuman, your experimental changes would be stopped. Others, such as a character I have received information on, will likely go through several changes and still come out looking quite the same as she went in.
And yes Cutter, I am sure that I have room for more people... I am actually about to repost this topic in the small groups request, and see if I get more people there.