Honestly I would seal the backs as George said and try and locate something nice and straight to cut your teeth on.
I'm sure those pieces can be spliced and turned into a really nice bow. But respectfully, I know that the likelihood you're going to nail it on the first shot is not high.
Chasing a ring, reading the grain, laying out the bow, fitting the TD sleeve or splicing the billets together, straightening the bow, tillering .... These are all skills to develop. And each one can derail or end your project if you go too far astray.
If you've got unlimited Osage and you don't mind losing it, then forge on, but if you want to ensure that wood makes a bow, you're best advised to do a test run or two with some clean wood.