Alright, so I'm to the point where I'm doing the Meeting the Hermit quest. My pets are leveled to 30, 28, and 26, and I've got some fairly decent gear. The issue that I am constantly running into here is that I cannot buy potions high enough levelled to adequately heal my pets. Because to buy potions that are actually decent for my pets, I have to be at "Friendly" with Saerielle, but to get high enough rep with Saerielle, I have to complete this quest line. Do you see where I'm stuck? Now to be fair, this is an issue I seem to be running into in many places and not just in Enigmatic Grotto/Faerina's Shrine.

TL;DR - Is there anywhere I can buy better potions other than in Saerielle?

Well, other than buying potions, you can get potions from doing missions (where you send pets off for a couple of hours and they come back with satchels that can reward you). Otherwise, the main strategy here will have to be lasting in battle.

(note, this is aside the main question)

I checked your party pets, and their stats are pretty even (except for the lvl30 pet who has twice the HP compared to the others).
In this case, having even stats all around isn't good for you. I can't tell if you're going for a tank build for the lvl30 pet, but stack all your points into his HP. As for your other two pets, pick between stacking all points into either strength or intelligence (whichever suits your equipment) instead of spreading them even. It's more effective to have them all stacked in one stat than otherwise.

Once you have a build like this for your party, it should be a little more efficient to take on battles in quests. (Provided that your "tank" pet with the HP is the center pet.)

I hope this helped. Also, here's a link to building an efficient party, tree-wise and equip-wise. c:
And here's one in less words.

Right as you posted this I've been redoing all my pet's stats. =w= I'm hoping that this is going to help out because without potions this gets to be super ridiculous.

Understandable. xD Also remember to get full mana before battles and be able to use Mend if you need it.

I personally recommend learning to do missions successfully. Never have to buy anymore potions if you do them often. c: I have like... hundreds of potions xD

I agree with missions being the best method to obtain potions.
a) you don't havre to spend gold for them
b) you earn gold with it in addition to potions
c) you get way better potions than that you can buy for gold (the only way to get potions of that quality in a shop is for badges)

Its actually fairly easy to become Friendly with the Sanctuary of Saerielle if you complete the Myconid Hunting mission in Faerina's Shine every day. There's also the added bonus of badges for the city.