I'm gonna put an edit in the first post to clarify what exactly I'm asking, cause this is a lot of answers that ARE HELPFUL YES, but not what I'm looking for right now-
But you are right that water is a multi-attacker with tidal surge... seems like with the fire suggestions, everyone's suggesting a multi-attacker. Maybe I'll consider water for the multi-attack as well as healing?

I could suggest using the water/air/(?) as a boss/ between boards/ bloom event team, and a second team for mob-farming for boards? This is a common strategy people use.
(As mentioned in our prior post, water's only multi-hit move has a 4-turn cooldown, and is only available at lv65+ (meaning enemies average 29k HP or more) so I'd say kinda *wiggles hand* for farming board points, but I don't run water on board teams so I don't know how it would do, these days (last time I ran water on a board team was before lg release/elements+proficiency overhaul so moves were different and lv60 was the level cap *shrugs* it'd be a different experience these days))


For the Water/Air/? team, you can co either Water = Tank or Water = Buffer
Water Tank, you could potentially run Light Healer, or a second attacker.
Light healer is probably the best option- while water can heal a team, it isn't as focused on it as light. Running water buffer you generally want the pet ranked so its ice barrier/ice sphere can absorb- and thus heal- more damage.

A second attacker is more dicey since, again, water isn't as focused on healing as light is, but is possible, and would give higher damage output than a second water or a light.

Overall, with these pets, Light Healer with Pyromancer or Lightbringer equips would be a pretty safe bet for team stability and longevity (especially given the level variance on the pets), though not likely to make a team good for wiping out mobs at a competitive board team speed (but how much that's needed depends on theme popularity and how much time you have to grind)

Pssst, if you ever want to try a fire pet out:
https://www.sylestia.com/view/pets/?petid=7548069
:-)

@Scathreoite
Funny thing, this is already my second team- My main team is a dark/dark/air, the air being Sandstorm! I love them very much, the darks are two of my oldest pets :]
Ah, yeah Limestone is definitely a tank. She's built for health missions, so she's got the highest health in my stables. (12-13k I believe?) That's why I'm not all too concerned about healing, but maybe I'm too comfortable because of my dark mains getting healing every other turn. Honestly I should just take the confirmed pair out for a test with a random light/water pet and see how it goes... I'm gonna go do that! I'll come back with an edit to tell you how it goes :)
Edit: alright, I tested it out with a couple of attuned pets that were level 56 for light and 62 for water. Honestly the light just seemed to slow me down a lot, since it wasn't doing much damage. And with both, I wasn't even using the healing abilities much if at all. Through at least 5 battles each with up to 3 enemies, no one got under 85% health. Honestly I think Limestone is just too good of a tank to need a healer! I think another tidal wave is going to be much more helpful than some heals that are just going to end up going unused and wasting mana. Again, thank you for all of the advice :]

@Faeyla
(quietly screaming) AAAAAAA SHE'S SO BEAUTIFUL YOU CAN'T BE SERIOUSLY JUST GIVING HER TO ME- AND MAX STAT TOO??? YOU GOTTA BE JOKING, YOU'RE JESTING WITH ME, WHAT IN THE- ahem. Yes I would love her very much and she would be a wonderful start to a level 30 team with my other level 0 Draeyl :D! But you have to let me tip you at least 10k, I can't accept a free purebred 6vis max stat-

Okay, I changed the price since you insisted. I'm just happy she will be appreciated. It's one of the few themed I've had chosen, so I am glad you like her.