Basic Shakespeare Authorship Issues

Before getting to the determination of who the actual author/s was/were of the body of work attributed to 'Shakespeare', a number of basic authorship issues might tend to complicate matters . .

• Sources: how much of what we now recognized as the works of 'Shakespeare' comes directly from the sources (read other authors)?
• Collaboration: who is thought/known to have collaborated with what we're identifying as the 'primary' writer? how many writers worked on a given project?
• Editing/proofing: what was the actual process for putting words down and getting them published? who stood in between pen and press? how were works reviewed/proofed? who did this actual publishing work? how was this different for poems than for plays?
• Players: from what version (from what provenance) of text did the players work to create the stage parts/roles? what was their subsequent input/effect on the texts? who directed the works and what was their input/effect on the texts? to what extent do versions of the stage plays we now have come from player memories?
• Interpretations/revisions: how were these player memories transferred to the 'original' published texts (folios)? how have subsequent interpretations and revisions (many over the years) changed the text? how does what we have now relate to the original works? ('corrections' and other revisions are always being made with each new printing)
• Contemporary understanding: how does our contemporary understanding of literary authorship affect the way we look at the question overall?

When I consider all the moving parts (as roughly outlined) above it certainly diffuses the discussion in my mind. I could see new discoveries in these areas at some point leading me to different conclusions on authorship.