Sounds good fdr,
BUT MCAS does not operate with flaps extended as I understand things. So then, do what you like with the flappery, it matters not.
A simple old engineer like me sees the easiest and best fix as small strakes on the aft fuselage set to zero incidence in the CRZ case. Now they cost a bit of wetted area and maybe a bit of extra drag on CLB coz the strakes do not align with the streamlines. However it is a simple once for all fix with no failure case. Never mind this software stuff, KISS.