RS,
Priming the resin parts will help with paint adhesion (be sure to wash the heck out of them with detergent before you use them), make sure you use a respirator or mask if you saw or sand (can't be too careful with the dust), and attach with superglue. You might need to slightly grind off bits of the fuselage wall to get the cockpit tubs to fit - just work slowly - and as they say in woodworking, measure twice, cut once. You can always take a little bit more off, but it's hard to put it back.
With the photo-etched parts, superglue is the go as well, but sometimes, for really delicate parts that will be protected from fingers, I sometimes use thinned white glue, paint or even Future to attach them. Painting these parts should be just like painting any other part of the model - just use care and patience.
Be a little careful when detaching the etched parts from the frets - sometimes the little bits can become airborne and can either disappear forever or hit you in the eye - that can ruin your whole day. Maybe lay a piece of tape over the whole fret and when you cut, the bit simply detaches from the fret but stays stuck to the tape - easier and safer.
Good luck and post some pictures of the Mig29 or the Su27 when they're done
Lee Tree