My 2017 has signed up as a two way C/RHP at all of the major camps and showcases and even into the Fall of his Senior year, it is still not clear where his greatest value is. Some coaches have focused on his catching and others like his pitching prospects because of his strong arm. Our experience has been to enroll his primary position as C (or in your case MIF) and then list Pitcher as the secondary. Every event he has been to, they have always allowed him to pitch at least one inning, sometimes each day like HF did. That way your son can get seen in both positions and coaches/scouts can decide for themselves the best fit. And several coaches have said they like the flexibility and it may give him an edge over a kid who only provides one option.
My son also got what I thought was some excellent words of wisdom from one of Stanford's coaches at one of the camps he attended. The coach said two-way players should continue to play both positions until they are set on a college team and that coach tells him to drop one of the positions. Until then, he said, play the position where your HS coach and travel coach need you the most and keep your options open. Good luck.