Yes the glues are long term stable as are the resins.
How strong is a piece of string lol. But the impact attenuator panels all have set ratings for how much force they can take before deforming and how much they deform. I could in theory use thier data to make a rear impact panel that can take say for example a 10mph impact from a 1 ton car with x mm of deflection.
That is ignoring the strength of any laminates over the top of the panel ie they will need to smash through the rear bumper and rear panel before they touch the impact panel.
In reality I have no intention of spending yonks designing an impact panel to take x, y and z force. It will be overengineered based on a minimum standard i am happy with. Im not aiming to pass NCAP just make sure its stiff enough to not be a death trap!