Can anyone suggest an easy way to create a template using a router, in the aid
of unusually shaped drivers for my baffle.

A guide bushing, spiral bit, and templates

you could replicate the front of the speaker in 3/8 mdf using a jigsaw and a sander, use a 1/2" flush bit (one with a bearing on the end) clamp or screw your replicated piece to the template material you intend to use, cut out, keep in mind this will make it 1/2" too large all the way around. put in a guide in the center hole (shrinks it by 1/2") set your depth and there you go.