1.) Can the Encore pistol be adapted to use a rifle stock and Encore rifle barrels? So, if I wanted to, I could maximize versatility? I see the Encore rifle has a set-up for 20 gauge shotgun and that would be splendid to be able take advantage of, plus the variations on single shot rifle. I'm mainly interested in the pistol mode, but to have rifle options would be great. [/size]
Yes
2.) I'm not a big guy. Can I handle recoil on this pistol? I shoot a .357 Mag pistol normally, about 100 rounds a session. I've owned a short barrel .44 Mag with no recoil problems. What do I need to expect here?
Size has nothing to do with handling recoil. I've fired a 260 Encore and recoil is more comfortable than my 44 Mag Contender.
3.) Can the .223 barrel handle 5.56 milsurp ammo? Some folks say you shouldn't mix these two up on some firearms. This pistol is going to be a "fun gun" target shooter for me mostly with an eye towards hunting with it in the future, so it's nice to use milsurp ammo to practice with for the price (as I do with my.308 rifle.)
I suggest you ask the factory, but I would think it would be ok.
4.) Is the Encore rugged and reliable? It sure feels like it, but I figure I better ask anyway.
Yes, mine has been so far.
5.) Any tips or suggestions?
Yes, get a trigger job done or learn how to do one if you're handy, and don't use a hammer extension, the hammer spur tends to break.