Where do I go from here?

I'm currently plvl 66 and lvl7 merry go.

STR:
5* g2 luffy lvl35
5* g3 luffy lvl29 (just got it)
5* alrong lvl57
5* edward newgate lvl14 (can't even use him yet because he takes up almost half the total cost right now)
4* arm point chopper lvl1 lol
4* alvida lvl39
4* mr.5 lvl29
3* laboon lvl10
3* fire pearl

DEX:
5* ashura zoro lvl45
5* lions song zoro lvl31
5* izo lvl21
4* guard point chopper lvl5
4* hachi lvl12
4* miss goldenweek lvl21
3* chef zeff lvl22
3* django lvl13
3* smoker lvl28

QCK:
5* diable sanji lvl35
4* mr prince sanji lvl17
4* tashigi lvl30
4* jozu lvl11
3* kuro lvl15
3* miss valentine lvl20

PSY:
5* sogeking lvl16
5* shanks lvl39
4* GP usopp lvl41
4* impact usopp lvl24
4* heavy point chopper lvl20
4* vivi lvl34
4* marco lvl20

INT:
5* towel nami lvl20
4* mirage nami lvl25
4* brain point lvl15
4* buggy lvl21
4* don krieg lvl42


I've been using a double arlong slasher team to clear stuff fast up to elite stages so I lvl'd slashers in general. But I also use double ashura zoro dex teams to tank (expert stage and heavy hitting bosses) when double arlong won't cut it.

I find myself not using INT or QCK teams at all and diverse lvling seems to hurt my overall progress. I'm guessing I should evolve g3 luffy asap but what about the rest?

I am confused you said he is g3 luffy 5*, how can you evolve him? But yes you should run a g3 luffy team with arlong, asura zoro, GP Usopp, and towel nami(or kuro just giving you nice diversity).

Of course you will want to cater your team to whatever fortnight isle we are on. For Krieg it would probably be best to have shanks instead of towel nami.

For Mihawk you can very likely take down mihawk with g3 luffy, arlong, alvida, mr. 5 and gp usopp.

With your current leveled units and a guest lvl 50 g3 luffy you can deal 356492 damage a turn which with 5 turns to attack using alvida and usopp is enough to take down mihawk (fairly close tho).

Oh my bad, yeah luffy is 4*. Im gonna evolve him asap. Thanks for the tips. Are you saying i could take on mihawk 40 stamina or whatever is the guaranteed drop?

With the team I stated:

lvl 29 G3 Luffy (yours)
lvl 50 G3 Luffy (guest captain)
lvl 57 enraged arlong
lvl 39 smooth smooth alvida
lvl 29 Breeze gun Mr. 5
lvl 41 GP Usopp

Yes you can handle 40 stamina mihawk, I would highly recommend you level up the arlong and G3 luffy as they have the best atk per level gains and you are cutting it close with the lineup I stated.

Feel free to make use of the link in my signature to look at the damage you can deal depending upon the levels of your units.