In each table after the row with enemies count by location there are rows that list the name of enemies, their level and type. R (red) for rock, G (green) for paper and B (blue) for scissors.

For arguably a little better-formatted tables see this Google docs spreadsheet[docs.google.com]

One of the most easy and rewarding fight for low-level characters is the one with Natsume&Mei on the school's roof.

Twilight Sky may also be a good location, although the fight may be tough.

Manager&Chris and Krilalaris rooms are not good for fast grind, since there is a chance your character will be disabled for a few turns.

Guild seems nice at first, but Grain is tanky and requires precious time.

If you want to grind for stars instead, it might be better to start a new game+, since the payout is the same, but the enemies are weaker. Just make sure you are starting again on a slot marked "CLEAR", otherwise it will erase the data. You can backup your saves (or even use saves you get from friends), they are located in Fruitbat Factory\200% Mixed Juice!\ in your documents; they are named slot00.sav, slot01.sav and slot02.sav for the three save slots.

As it have been noted in comments by Kurogal, there is an easy fight with great payout in experience just before fighting a final boss, in Episode 6, Map of Red Barrel, Town.

One episode before that, there is a good spot to get 60 stars from battle with one enemy in Bushes. Note that this is a fight with high level Tequila&Mescal (Pig) though.