Not recommended.
Yes, Ruger made them
50-200
Ruger.
Ruger 1022 .22cal rifle (semi-auto) Remington 572 Fieldmaster .22 (pump)
Ruger's web site has extensive sn data.
Depends on what caused the jam.
75-300
Check the receiver and barrel
Yes, there are a variety of magazines for the Ruger 10/22. I have seen them advertised that hold up to 50 22LR bullets each. There are also magazines that hold 20 or 30. The standard magazine holds 10. If you use "magazine" rather than "clip" you will get better results in your searches.
Depends on the store.
it is worth ..............$$$$
50-200