Hi Hillbilly, Russian olive and chinese elm? Sounds like you're out on the great plains. I think you'll find that both can make decent bows. I haven't used either yet, but others have stated that each can be treated as most white woods. Just remove the bark and let the outer sapwood ring be your back. Chinese elm ( and I assume you mean E. siberiensis) is lighter wooded than many other elms and should be made a little wider. The wood may be a little weaker than the american and slippery elm staves I've used, but I bet it is still tough to split! Here in CA Chinese elms are E. chinensis. I haven't heard of, or seen any bows made from that species yet, but I suspect that it would work well too.
I know BCBull ocassionally cuts russian olive. Maybe he'll give some of his observations.
Ron
PS I'm still looking for a russian olive stave to try. If you get some extra staves and want to trade, give me a pm.