Just to close the loop on this: I did a sample door, was OK with the durability, the customer liked the appearance, so I accepted the change order and did the work. The Insl-X primer sticks as well to the particular laminate as any primer would stick to anything - you could scrape it off with a scraper or by working hard with a thumbnail, but you could damage most primers on most surfaces with the same tools. We sanded the edges to ease the hard laminate corners, sprayed primer and sanded, sprayed primer a second time on a few of the doors, and sprayed a couple layers of finish. They look great, and I'm comfortable that they're as durable as they need to be.