Coliseum normal battle

Is there a script that allow the K.Oed character, or under status (like Imp or Poison) to fully restore their HP, MP, & remove all negative status, after they win or lose the coliseum battle?

It can be done by event. The colosseum fight is at $CB78E9, if you put a hook (B2 command) at $CB7972, you can do your restore/remove HP/MP/status there. It will work for every colosseum fight except the Shadow one, which the after fight event is from $CB78F4 to $CB796B. However there is a branch to $CB7972 if you exit the item choosing menu ($CB78DD) so you might want to copy the $CB7972 code elsewhere and branch to that for this case to prevent HP/MP restore by simply entering and exiting the item betting menu. There might be a better way to do this, idk.