Question: Is there any real world concern re mounting my fittings for the front deck on the surface using epoxy as the "glue" per normal building practices???

What sort of fittings are you installing? You definitely want your deck line fittings to be solid and reliable. Things like paddle holders aren't so critical, IMO, but it is embarrassing when things fall off your 'nautical craftsmanship display' aka boat project. ;-) .

If you have exposed joists overhead, I'd suggest an experiment: Glass a short section of joist edge, and then glue a fitting to the glassed joist area. Put a line through and apply body weight.

BTW, you might be surprised what you can accomplish with a helper and a piece of pipe on the end of a socket wrench. I installed padeyes 'way far' from the cockpit in a bulkhead-less and hatch-less Mariner boat once - it takes a helper on the screwdriver, but it can be done with patience and a bit of mastic to hold the nut in the socket.