Always seal the ends of ANY log or staves asap after cutting. I use shellac. It dries fast, and then I give it another coat.
Best case scenerio is to split both promtly.
Treat black locust like osage. Cut the log a little longer than needed, seal the ends, split out staves, and remove the bark and sapwood as soon as possible, preferably bringing the back to a single ring, then seal the back. Again, I like shellac.
Hophornbeam, cut while the sap is up, split into staves, the bark will peel off easily and that is the back of the bow. Seal the back, or it may check.
Again, this is best case scenerio. Black locust logs can sit for a while with the ends sealed, but the longer they sit, the greater the risk they will check through the bark down into your bow wood. Hophornbeam should at least be split into staves right away to begin drying, otherwise it will degrade internally.