They better get back to the drawing board for the next Marvel vs Capcom. That Infinite crap wasn't the business. Especially with the very noticeable absence of X-Men and Fantastic Four characters. It wasn't good in my opinion. I really hope we get a better and well thought out game this time.
And not only that, but only giving us 5 new characters at launch while locking the rest behind a paywall was pretty shitty as well.
But to answer the OP's question, no. It's called Marvel vs. Capcom, last I checked. Guest characters work for other fighters like Mortal Kombat, but not MvC.