I know what you're referring to, but it's a bit different. It barely locks together (as opposed to traditional laminate where that shit like actually clicks in). I'd recommend you go to HD and check it out to see exactly what I mean. The level 1 can be cut with a razor, but the level 2 needs cut with a saw.
Hmm- I usually don't put a barrier down with this stuff. I'm sure it wouldn't hurt, but when I first started using it, HD explicitly told me it wasn't needed, going over any material. To be fair, I've only laid it over concrete twice, so majority is over wood/existing laminate.