The hull will require a massive redesign. From what I understand, the cutter has a completely different criteria for survivability (it doesn't have to worry about naval mines and Chinese AShMs). And that's just for starters.
The weapons and power requirements are completely different from a cutter as well.
Now the good news is that if memory servers correctly, HII basically made an FFG(X) bid using the Legend class as hull base. So a lot of conceptual development is probably done. The bad news is that this bid was rejected probably for the reasons I outlined. Too many compromises made in terms of survivability and weapon systems.
Though argubaly, a cheap OHP style frigate is just what the Navy needs.