Haven't seen anything on HQMC's aviation plan about it. My guess is they'd just go away. VMX-22 does the OT&E stuff that HMX does with Phrogs. No real need to duplicate efforts. Unless, they want to use it for VIP hops/frags...
Check out page 5-11. It says they're planning on transitioning from the -46 to the V-22 starting in FY17, planning on 2 V-22s the first year and 6 in FY18.
I'm assuming that those aircraft will be used in the support missions of HMX. I suppose it as some assets in that role, namely the self-deployability and commonality with the rest of the Marine Corps.
I don't know how seriously the V-22 was evaluated for transporting the Man, if at all. I think the public controversy over the aircraft probably made the idea problematic, pros and cons aside.
The executive transport mission requires near 100% availability, not a fleet average 65-80%. The parts priority that would require for the V-22 would probably cripple the rest of the transition, in the sense that a part needed for a combat unit would automatically go to HMX if needed there, not to Iraq/Afghanistan. That's one issue alone, out of many. Also, the president only does very short flights in helos--the speed/distance advantage that the V-22 delivers doesn't make enough difference to offset the other factors. The V-22 might come in handy for some missions they do, but not the daily pres/VP transport frags. Pure speculation on my part, no inside knowledge other than casual familiarity here.
They're offloading most of their R/W OT&E to VMX-22 as well, including the 53K, so HMX will probably get a bit smaller over the next few years.