You could probably do a good engraving by removing the polyester paint with the laser: Polyester - Laser Cutting and Engraving Polyester | ULS
I don’t think you’ll have any luck getting through the aluminum if you tried to cut it, and even if you did, Polyethylene tends to melt on the laser rather that cut cleanly, so you would likely not get a good result.
The Shopbot is probably more appropriate if you want to cut it.