A bolt out of one rifle into another may not headspace correctly. I wouldn't try it unless I had the headspace checked for both bolts. Of course, magazine and bottom metal is different for the ADL vs. BDL, not sure about the P or CDL.
In lieu of getting extra components, I'd get extra of what is most likely to be damaged. Extractor, springs, etc... instead of an additional bolt, magazine, stocks, etc...
Then again, if for use as an emergency type rifle, I wouldn't go with a Remington to start with. Too many instances of bolt handles popping off, extractors breaking, AD's and the like for that.