Ash saplings make good bows if they are not too short...unless you back them with something. You can peel and rub it down with fat (or wax) but it won't make too much difference in the drying time compared to a clean stave. Ash dries pretty fast (may 2-3 months) in a dry environment. Twice that long if humid.
Your description of how to prepare and season a stave sounds like a description of the way Native Americans did it. There's nothing wrong with that approach but it's not the only way.
I'm sure others will chime in.