Any secrets to bedding an action to an ejected molded gun stock? Thank you for all answers

Clean it real good. Scuff up every contact surface.
Grind undercuts or angled holes into any surface you can.
You are looking to create mechanical locks. The epoxy flows into
those and locks itself in place.

I believe that I read to clean the surface with vinegar. Got that from one of Mule Deer's Gun Gack books.

Problem is a flexible stock will still be flexible.

Yeah, its a problem. One of my most recent:

I've bedded a bunch of them as well. Creating mechanical lock is a must-do and I've heard everything from cleaning with acetone to using a soldering iron to roughen the surface, I've tried it all, it all worked the same, which is to say: it all worked well.

You can stiffen the front end by filling it up the hollow area in the fore-end with marine-tex. I have only done this once, on a Remington plastic stock, but it went from very wobbly to pretty stiff. I also stuck a carbon fiber arrow shaft in there but I am not sure it actually did anything.

Long story short: I would not hesitate to bed your plastic stock.

I wonder if you can flame treat the plastic.... excuse me... "space age polymer" for epoxy adhesion the same way you flame treat it for paint adhesion.