Yeah, the Justice League's are really two half-hour episodes back to back with the credits shaved off...but since the episodes have already been two or three episode stories, that works fine.
It's interesting to see how they introduce classic villains and characters of the DCU into JL. This week's 'villain' was never actually named on camera, although his name showed up on a paper displayed prominently during the episode. He also looks nothing like his comic-equivalent, but that's not suprising, given how retro that character was.
I'm really curious if we're going to see a Starro episode in the near future. That could be fun.
With respect to the Teen Titans, they've made no reference to any continuity outside their own, and I believe the producers made it clear that it was intentional. Technically, this series might take place in the same world at Batman, Superman and JL...but we have no way of knowing. They've done nothing to contradict or confirm it, and may be still deciding themselves.