I agree we don't know the exact timeline. And I also agree that with a lot of season 4 they just wanted to dump in the drama. They were attempting to become a more mature show, but they really just became a super depressing soap opera for a little bit.
I'd disagree that Justin heals from his bashing quickly. We see evidence of him being off throughout the whole season, though his initial shock of being in public does go away after a couple of episodes. (But really, was Brian going to help him walk everywhere for a whole year?) But him leaving Brian for Ethan, I think, is huge evidence of him being rocked by the bashing. Season 1 Justin never would've done that. It's part of the reason their breakup is so heartbreaking.
Yes, Ted and Emmett. I wish they ended up together, too.
I still forget about Blake all the time...