If you take the bark off the sapwood has to go as well, sapwood dries quicker than heartwood and will badly crack your stave even if the sapwood is well sealed.
The bark has wood wasp eggs in it, if you don't have time to get the bark and sapwood off all of your staves you need to spray the bark with an insecticide. Powder post beetles are the worst, they go in the top of the stave and out the bottom, wood wasps work on the sapwood and first layers of heartwood first, if caught in time they can be stopped.
Start your belly split with something like a couple of screwdrivers pounded in following the grain you have marked. Some osage cores split off easily and cleanly, some run off to another grain and may make a thick end and a way too thin end.
Don't get greedy, it is better to have two good staves than to shoot for a third and have a split go cross grain and mess up a lot of wood.
4 coats of shellac on sapwood, where I live the sapwood always cracks if left on, after I had a bunch of ruined staves from being lazy, I never leave the sapwood on a stave if I take the bark off.