I always suggest healers because of the debuff clearing and general awesomeness, but if you were a fire main with Death Mirage + a leech like Gai...

Since you're lightning you're able to leech, which means the only issue is poison, etc. I agree with Overmain - put your best-attack/attack-triggers-combo ninja in first place, up your initiative through refinement... it makes you faster, which is awesome in ranked.

If you were to use a healer, I'd find someone "multi-purpose" (I made that up ^_^) like Kabuto (clones), Karin (poison), Kurenai, (shield) since all of them do more than one thing and, depending on talents, combo well too. If not, maybe... Kiba GNW (who self-heals and heals his "clone" Akamaru, but he's not actually technically a medic in my eyes), a leecher like yourself, Gai, or Lee; a reviver like Chiyo and probably one of the Pains, a debuff clearer like the fire main, Hanzo if we ever get him... yup.

Depends on your tactics - if you feel like you don't have room for a healer - say, Kabuto heals, combos, clones but doesn't set anyone on fire or whatever - leeches are really good. If your goal is staying alive long enough to get a huge one-shot kill in, Lee/Gai is a good pair to have because they both leech along with your main, so you have backup. Plus Lee's move costs no chakra, which allows for other moves, and Gai's move interrupts, which is part of the "staying alive" thing.

If you want another interrupter (I think lightning main interrupts too, but don't know if you have to give up leech for that), Neji would be good. Problem with Neji/Lee/Gai is that there aren't any clones/shields (Neji's rotation catches some tai but not all) so that'd be a pretty major weak link. Same with Tenten - all of the teams I've fought that had her have had killer combos, but again she doesn't clone/shield. As for the next member, maybe experiment a bit agains Kakashi's clones; pay attention in Ranked Battle to who's causing the most damage/who's going down the fastest, etc.