I feel that of the one-off characters to appear in a Simpsons fighting game, Poochie and Hank Scorpio are both the top contenders with how popular they are and how easily you could give them a moveset; Frank Grimes and Lyle Lanley are equal to them in iconic factor but lag a tiny bit with moveset (not to say making a moveset with them is impossible of course); while Ruth Powers and Gabbo don't have as much of an iconic factor (yet again, not to say they're unpopular or obscure) as Grimes or Lanley do but have more moveset potential.
The second reps are kinda questionable in my opinion, but good job.