To my novice eye, there seems to be a lot of overlap in their respective wishlist. The big difference would seem to be in the need for ship-based operations but perhaps the perceived benefits of a joint program may once again hold sway.
I'd say it probably will be a joint program, when sat alongside the F-35 program it's clear that by-and-large the more severe engineering challenges sat with the B with the A and C versions going relatively smoothly bar the latters problem with it's tail hook.
Would it be a bad thing? Not particularly IMO, question being for the AF would this be the follow on to the F-15 series and to supplement the F-22? Because if that's a yes, and it's a supplement as opposed to something which will become the
replacement for the F-22 then it could well become an international program with less caveats than originally thought the way that the F-15 has developed.
For the RAF, the timeframe of 2030 might be a bit soon and this is because the Typhoon right now is lacking a number of systems that allow it to unlock it's full potential which come with the Tranche 3 (and to a degree Tranche 2 IIRC) with ability to fit an AESA radar & conformal fuel tanks. Add on integration of Storm Shadow, Meteor and Brimstone 2 onto that list too as well as probably a wider selection of the Paveway series.
But if the projected time is 2030, then it'll probably be more like 2040 which by that time makes the Typhoon getting close to 40 years old.
Interesting aircraft specs though.