Possible. RSN is buying the Slyver launchers separately. While initial batches could be A43 launchers(im not even certain about this), the remaining batches could be A50s. As I`ve said, the A50 launchers were still undergoing testing when the Formidables were being built. The tests were pretty recent as well.Are you posting as a fact or as a question? If question, then the answer is no, at present.
The Formidable can accommodate as many as 48 cells in front of the bridge afterall. My gut feelings is that the Formidable could possibly end up with A70 launchers(or a version of it) in the end and the RSN is actually waiting for the latter to be ready. I dont see a problem in installing them on the ship; especially if you consider the fact that she would not have a problem in putting on Mk41 tactical or perhaps strategic launchers. That would give the RSN the flexibility of putting a variety of other missiles in the launchers in the future(im assuming that the A70 launchers will be made out with that flexibility as I`ve read about it sometime not too long ago).
A version of PAAMs, the SAAM AD(consisting of both Aster 15s and 30s) is already available; for the anti-air FREMM version I reckon. That could be a possible make-out for the Formidable class; for a possible 32 Aster 30 and 16 Aster 15 missile load-out in war-time per frigate.