If Lashley signs with WWE, I think he'd be better served being put on the main roster. For one thing, Lashley's in his 40s now so you have to think that there's not a huge window of opportunity to get the most out of him. For another, I've heard that a lot of fans are salivating over a matchup between Lashley and Lesnar so if Lesnar is sticking around after WrestleMania, it's easy to view Lashley as a top opponent for him. As we all know, Vince do love himself a hoss and do love himself a hoss fight.
Ricochet, Candice LaRae and War Machine are all reporting to NXT, according to reports, and that's probably for the best. Outside of indie or internet fans, nobody knows who the hell any of these people are and a great thing about NXT is it gives them a platform to present themselves to fans before hitting the main roster. I'd say they'll all thrive in NXT but it'll be more of a crapshoot when/if they make it to the main roster because it's obvious that Vince and Triple H aren't on the same page and don't have the same vision for some talents.
As for EC III, don't really care either way.
Of course, maybe the wrestlers from Impact aren't on the WWE's radar as much as you might think. Lashley and EC III were big fish there but that's not exactly saying a whole helluva lot when you consider that Impact Wrestling barely registers as a blip on the radar and has been that way for years.