Vitek: I thought of that but they don't seem like they are on the "bad" side in that trailer, so I dunno.
Is there even to be something like Remnant in new SW movie universe?
They wiped the universe, so there's no telling. There used to be, though, and yes, they had Stormtroopers, TIE Fighters, Star Destroyers - the lot. They even survived and signed treaties with the NR.
Also, to reiterate, it's a teaser and not a trailer. It
teased Stormtroopers, but we never got any hint where they were, who they were with, were they good/bad/neutral. We can only conjecture at this point, given what we know of Star Wars and Disney.
My personal conjecture would be that Disney will try to keep a simple good vs. evil storyline, therefore the faceless troops will likely be part of an evil imperial remnant. Not necessarily a bad setup (worked for the original), but I can only hope there's a tad more nuance to it. Still, pure conjecture. Also, I'm keeping it simple, so there's minimal disappointment ;)