borderline_dnd:
How important is it for the characters to have come from a RL DnD group? If it is important, what is the backstory for this RL DnD group? How much do these players know each other? Etc, etc. If that doesn't really come into play, then you may want to consider leaving that out.
It's not completely important and 'native' characters could be allowed. I just thought it might be a fun twist. I was basing it more on the new 'Jumanji' instead of 'Guardians of the Flame'.
I was thinking that the group is reuniting after a long hiatus (several years). Some might have reasons to stay (illness, unhappy with their current life, etc). Some have reason to return. (Have family waiting... the jock doesn't want to be a shocking girl... the pretty girl doesn't want to be a half orc barbarian, or maybe she likes being strong... etc.)