My recommendation on how to choose a swimming style? Find a swim instructor or coach and talk to them about your goals and personal strengths and weaknesses. Nearly every pool, public or private gym, in America will have some sort of associated swimming program.
A good coach will be able to determine your abilities very quickly after watching you swim, and will be able to suggest strokes and training techniques tailored for you. Nearly every stroke can be altered to accommodate physical disabilities, and swimming itself is very low impact sport.