My old party was composed of two offense and a tank. This is because, for the majority of the storyline in Umbra Forest, my pets were at least ten levels higher than the level of the area. I simply didn't need a healer. Now, I can only assume I am struggling because I lack one.

So, I have purchased a team of max and superstat pets to train for the Lost Grove. I do not want to attune them as I did before, as my pets were struggling more that they should have (my tank was destroyed after like three normal battles). Any suggestions on what elements I should use? Or more of, what combination of elements?

People have different preferences and it depends on your style of battle, really. Personally I prefer shadow/light/air. But you can replace shadow with earth or air with fire depending on which you like better. Air has its damage focused on single combatants while fire attacks multiple combatants.

It's worth noting that the Lost Grove is HARD even if you're at the necessary level to enter. You're going to struggle at first no matter the team you have. Getting wiped by a sprite is practically a rite of passage. You just have to keep battling through and continue to level your team. The Lost Grove also offers move ranks. Moves will eventually level up and get more powerful after using them a certain number of times in the LG. It helps tremendously and I can guarantee you'll see a notable difference after your moves rank up for the first time.

Thanks :) Nice to now I'm not the only one who got destroyed the first time in, too.