When jason bright and the ghouls left novac in their rockets, where did they go? possibly the divide?

In the ending slides, they can potentially end up back at Novac, and help the town repulse the Legion during the second Battle of Hoover Dam.

they went to a fiery and explosive death several seconds after launch...

Nope, the way the game indicates it, they went off to some perfect planet or something in space, and potentially come back, but the Divide is made out to be a hellhole, so I doubt it.

in the ending slides it says several members of the bright brotherhood, not all of them