To continue along in the vein of talking to myself....
Karharath, since he apparently committed treason during wartime, could have felt that going directly back to Sharn would be a bit difficult and spent some time hiding out in a small Kalashar village....
The kind of village where Amalkhad lived. Which could have lead to wacky hi-jinks that caused them to get to be 5th level (which is pretty special in Eberron terms).
Of course since we will all be 5th level, and being that powerful is a pretty big deal in Eberron anyway, the links between characters may not be so important.
[I also noticed that the lines of both Had and Rath make an appearance in the Races of Eberron book. Unfortunately the actual details of the lines don't make much detail. However the Had line seems to have a powerful seer, which, I think, fits well enough with the theme.]
Sorry to keep flooding posts, will wait till people get back, etc.
(but some discussion is better than no discussion, even if all the ideas aren't winners, no?)