I wouldn't try to pretaper lams, just don't get crazy with R/D or recurves. Layers can run off on the belly as you thickness taper just like growth-rings can, but if you are making a pyramid bow, that shouldn't be a problem. You can even lay up your fades into the handle stairstep style with veneer slats before gluing on a handle block, but it WOULD be good to get a power-lam in there if you can so your handle can't pop off. Less likely to if laid up with veneers, but power-lams are the thing for this.
Most veneer is too thin, but 1/16" should work. Get lots of good clamps, though, and the right glue; every layer is a chance for glue line failure to occur.
Lastly, just like any backing, DO NOT SETTLE for less than perfect grain. 1/16" maple backing had darn well better be perfect.