family sharing

I have just returned to Apple and iPhone products after a 5 year break. Waaaay back when... I used to go through iPhones and Apple ID’s with regularity. Mainly due to theft and forgotten passwords and inability to recover accounts. Now I have regained access to 4 different Apple ID’s, all of which I had used to purchase content thru iTunes. Unfortunately Apple will not merge the Apple ID content allowing me access to all of it on one account... I am told that now thanks to family sharing I can “sort of get around this”. I have a couple of questions ...

Question 1... I don’t suppose I can just sign up for the $14.99 monthly subscription, then add all my former Apple IDs as family members and elect to share iTunes purchased content WITHOUT ACTUALLY setting up each Apple ID on a separate mobile device or computer?

Question 2... waaay back then music streaming services were not around like now. Purchasing digital music or stealing it from lime wire type websites was the norm... I opted to purchase. Now it seems I need to pay the monthly Apple Music subscription if I want to listen to my already purchased and owned musical content on my iPhone...? Whether single or family plan.. I still need to pay monthly to listen to the music I bought and own.... on my iPhone?

Question 3... I also purchased a great deal of music through Amazon during my Android years... is there ONE single iPhone app I can have my iTunes, Amazon, and uploaded (burned from my CDs on my computer) music easily available together for my listening enjoyment?

Thank you to those of you who help out with answers.