In regards of Fucko, here's some tips: Before you fight any enemies, grab the Potion of Potential behind the river puzzle, and give Fucko +3 ATK (if you still got the Beard Serum, let him have that as well). Then go straight for the underwater section, talk to the giant slime, and unlock Nick's location. Before you head there, grab the Magical Leaf from the chest above the black cat NPC, and give it to Fucko, so he can level up faster.
Then go to Nick's home, talk to him, and get The Sea's Song (the shell) to give Fucko some more stat points. But most importantly, grab the Stinker! It lets Fucko attack twice per turn, so not only does he double the damage (with crit chance), it also doubles his TP gain per turn. Then give fucko every item that boosts his ATK even further. One of the unique hats, the Biker Jacket from Skunky Hunk, the Broken Unbreakable Shackles (from Duiro's boss chests) or Spiky Gloves, Spiky Cockhugger and Spiky Boots from Hunkypunk, and a Ruby Ring, which you can craft at Wizzy's (and a second one, for once you're done leveling and you wanna get rid of the Magical Leaf).
Then go do the farming with the enemies, but try to get them all to join the base as early as possible, so you can watch their scenes and get extra stat points right away, which you all sink into Fucko's ATK. (If you still haven't unlocked the scene for dying 5 times, you can also do this on Pine Island for one more stat point). If you do all that, at lvl 13 he'll already deal 75-150 damage per turn with normal attacks alone, depening on your luck with crits. Fucko starts a little slow for now, but he's got mad potential later.