I can only respond to #1. The best connector is no connector. Even worse than any single connector is using a connector to a connector. Using an adapter between a spade connector that is fixed to the end of your wire and a banana jack is not a good idea. Decide whether you want to use the spade straight in, or not. If you want to use a banana connection, then remove the spade connector and solder on the proper male banana plug. (There are some very nice ones that essentially consist of a piece of copper or plated copper formed into a banana shape; simplest is best. Can't recall the brand.) Better yet, if you can fix bare wire to the amplifiers, do that.
As to the rest, you have a fairly sophisticated system for someone who claims to be "new to the audio world". What you will get here is naught but a collection of opinions from a variety of individuals who won’t even agree with each other on what you need or what you should do (including me). Follow your ears, is my advice. For example, I wouldn’t have a Linn TT, but many sane persons love them.