All I know is you need more than one. I grew only 1 this past season and the only tomitillo I got was pollinated at the nursery. I went back to let the staff know to not sell only one. I don't think most nurserys would even know the answer to your question
.I am wanting to try a few different kinds next year as well. But the plant I grew was not very much like a tomato plant. It was more woody. I would think that if there has to be two to pollinate, then there would be a good chance for cross pollination? Anyway good luck next season!