Yes sinew will work, the issue you may have is getting a good bond between the two. To get around it you need to size the ipe with 10 coats of 5% solution collagen glue, with drying time inbetween. You should end up with a shiny surface.
Ipe cannot be heat bent at all.
Bamboo/hick will both work very well as a backing for ipe.
Bamboo I would reduce to about 1/8 thick at the handle to 1/16th or so at the tips. Hickory works very well at 1/4. No need to worry about overpowering ipe!