I think the issue of all GC's claiming their properties back is just not going to be a realistic under a solution. As too much time has passed and TC's have built their lively hoods, further more, they've made the thing alot mroe complicated through mainland settlers and exploiting land to tourists.
However, if we fight for a fair solution the TC's and Turkey should prepare themselves for huge compensation cases if GC's can't return.
It's probably gonna be a mixture of GC's claiming back what they can, some people leaving properties in the north, and new homes being built.
As for these holiday homes, under any fair solution it can only go so many ways, either demolish it and return the land with a small compensation costs. The GC inherits the holdiay house as compensation and leases it to the occupant for rent. Or the occupant or Turkey will be responsible for paying the true current day value + compensation for not being able to claim it for 30 years.
Either way, there are a bunch of negotiated outcomes that can be disccussed to settle property. All i say is that in any fair solution which should be fair but yet practicle if you want a solution, don't expect an GC's to lose their property empty handed just for the sake of a solution.