NO
No, the Remington Model 1100 stock has a hole (recepticle) through the inside of the stock in the pistol grip area to accept the action spring tube. The Remington Model 870 stock has no need for this hole so the 870 stock will not fit on the Model 1100 action.
no
No
Remington 760 magazines made to hold the 35 Rem or any other of the short action cartridges...i.e 308, 243, 6mm.
Yes they are interchangable.
no
no
no there are some minor adjustments to the safety area
yes it will all you have to do is to take it apart
No
No, they do not. I called the company directly and they recommended a grind to fit model.