Yeah, loops would work just the same, but you will have to program breakdowns by hand, because it's not likely they will have the exact beat you need. Blast beats, double bass and simple 4/4 beats, which are generally the only loops I would use, are the easiest to program. it only takes as long as it takes to click all the little boxes.
As far as the song not feeling right, thats why I have the singer sing over top of the scratch guitar and programmed drums. The singer will be able to tell if the tempo isn't right, because his vocals won't flow the same. It's important that the whole band is present at this point. Remind the drummer to be mindful of the tempo, and confirm that he will be able to play at that tempo comfortably.
Anyways, I hope this works out for you guys!
:Smokin: