Your symptoms sound to me like an epiretinal membrane. This condition affects central vision only; it will not cause blindness. The surgery would probably improve your vision, but the double vision might remain. Your best bet for eliminating the double vision would involve peeling the ILM as part of the retinal surgery. (I know this is technical info, but definitely mention it to your retinal surgeon when you go for the second opinion.) My best advice: get more than one opinion from very experienced, board-certified retinal specialists before proceeding.
Neither of your questions can be answered in these forums. Get a second opinion on your eyes from another retina MD. If they are both the same then believe them.
JCH MD