Do you have a manual for this thing? I’m looking at the procedure for changing it on a FWD Colt, and it includes removing the power steering pump and bracket and the A/C condenser fan. Maybe the thing is installed in such a way that you need that PS pump bracket off to get the last bolt off?
If you really truly are sure that you have all of the bolts off, and this is a V-belt type alternator you should be able to wiggle around to adjust the belt tension, you should be able to get in there with some sort of prybar and wiggle it from side to side until it works loose. If it’s a serpentine belt, you can try the same thing, but you have to be a lot more careful that you don’t pry in a direction that will damage anything. A few gentle raps with a rubber mallet might help free the thing too.