Just an FYI here: heating epoxy (sufficiently) will overcure it and make it removable (it'll puff up like popcorn, and becomes very brittle and weak). I can't swear to the current state of the art, but using epoxy as a conformal coating to exclude environmental influences and thermally stabilize a populated circuit board was pretty standard military/aerospace practice in my day, and one could use standard soldering tools to drill down to the components for replacement/repair.