Despite the variety of answers you've gotten, no-one recommended you to strip the bark and leave it round. No-one recommended you to dry the wood outdoors. Do what the others told you. You don't have to split them down the center with the band saw, but remove at least a third of the belly thickness, so you won't get drying checks in the back. This is especially important for the black walnut sapling where you removed the bark from. A round sapling with the bark removed WILL check badly very quick. Reduce it to near the pith to greatly reduce the chance of checks forming.
Drying outdoors is never good, especially in such unsheltered conditions. The sun might hit it, the rain will poor down on it, bugs consider it a free meal (despite the bug spray), and fungi are not bothered by bug spray. Move all three staves indoors (or a shed/garage), and remove some belly wood from all three of the saplings.