If you are looking for an LF that is associated with a lawful faction, the Hussar for the BPA or Liberator for the LPI would probably be the most sensible choices.
We in the BPA are very active as you have specified, but LPI could probably do with more members if you want to help them.
Right then. I'll think about all the suggestions you have provided, and will make the decision this evening (Note: the Brets have a slightly larger chance of a new member, but that can change, too)