That is an Elb style hickory backed jatoba, aka Brazilian cherry, much harder than ash; stay with the flat belly on your ash, and make it wide enough, you'll sure end up with a better bow.
Yes, osage is much better for the purpose, maybe have a thin layer BW under the osage, or crown the osage with it, but let the osage do the job!
BW for handle overlay would be nice for sure, and no problem!
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