I'd go with floatation in the cabin, which should pull it up most of the way. Air mattresses, inner tubes, used polythene barrels (from a photo processor or bulk food importer--they both throw them away) would do. Remember that the air will expand in volume as the boat rises--so your "balloons" will burst unless they can also double in size or vent. If you use air mattresses or inner tubes, only inflate them half?way.
If you can get it off the bottom and rig a bridle around it, so you can put floats on either side and secure them low down, then you may be able to float it up the rest of the wayto the point where you can open the drains/seacocks and get it dewatered signficantly by itself.
Home Depot and tool rental stores all rent "trash pumps" that can get the rest out, once you beach the boat.
Just remember-things can and will shift unexpectedly, this can be dangerous. If you can find a local vendor who uses a small crane to move large moorings--they may be able to lift it all the way up and out, if your diver friends can rig the slings on it properly. Might be worth the expense to just get it done that way, without risking anyone while it is in motion.