Well, many of you guessed it! It was Sawsbuck.
I had considered Delibird, to keep the "bird theme" going, but...not the best rule 34 material, honestly D:
The final version of v4 will be coming out either Monday or Tuesday. Delcatty's interaction will be pushed back being more of an early v4.1 release. But she won't be coming out any later than I would have otherwise done. It's just an arbitrary versioning decision. I just want to get v4 out to the masses before the year's over ;)