Good. Amoxicillin is not a contraindicated drug for MGers.
That Pred withdrawal schedule sounds lovely, up until the point it doesn't work. If you begin having those symptoms I talked about, especially increased weakness, see a doctor right away. The withdrawal may need to be modified (smaller increments like 1 mg) or you may need additional treatment while you are doing it (i.e., plasmapheresis).
FYI, here is one study that has been done on familial MG. There are more.
Study of the prevalence of familial autoimmune myasthenia gravis in a Spanish cohort. - PubMed - NCBI
Annie