Thanks, but I'd also like to hear this from a met, but here is my guess:
The outflow on the NW side is being impeded on the last couple of frames, and that would be the impact of the ULL in all likelihood.
The degradation in convection between the outflow, and the core, may be related to some drier air being drawn in from Cuba. I missed that possibility before, but saw it when you asked the question.
Based on satellite presentation, at the very least I am not expecting any signifcant strengthening in the short term unless it could work through some of these issues.