Would a Rose Conrtol App similar to or added to the H9/Factor Control App be do-able and likely?

I don't think so. They are totally two different products. 

I just heard that there will be a software editor for the Rose in March, which is what I meant by my question, so that's

great news!!

There's some misunderstanding over that video.  At the moment there's an update app and a basic preset manager, but there aren't really any plans to do an H9 Control-style app.