The Harrier's only real USP is its ability to embark, so disband the entire RAF side of JFH and give the whole lot to the FAA. They can keep the NSW or form 2 unique squadrons again, and use it to cover training with the existing carriers and to maintain their cadre of FJ qualified pilots until JCA and the new carriers arrive.
5 Forward 6 Back - Its a grand plan but one that fails to take in a reason it was shouted down by FAA/RN types last time any change to the current manner in which the JHF is supported was mentioned. It wasn't purely because they believed it was part of some grand conspiracy by the RAF to do away with the FAA (which never would have happened anyway), its because they were fearful of any unpalatable alternatives that were offered, such as the one you mention.
At the moment the lion's share of supporting the Harrier (and thus keeping the FAA in FW aviation) is paid for out of the RAF budget. The RN, what with its aspirations to have carriers, n-boats and all that fine stuff that sits in the water, couldn't afford to support its own FW assets, at least not an amount that would be of any use. This is one of the reasons the FA2 was binned.
Of course an RN type would say "well the budget would transfer across with the aircraft", but if the role that was being undertaken by the the Harriers for RAF is still required then the budget assigned to the Harriers would be needed to support the remaining RAF aircraft that have taken on that extra burden. After all you can't utilise an aircraft more with the same budget as before and expect cracks not to appear.