- The lowest level I would attempt the hag quest with is level 5. For ironman I would even suggest Level 6, just to be sure. This is probably the hardest battle in act one ? Level 5 is maybe the biggest power spike in the game. Warrior classes except for Bards get their second attack (Warrior Bards only gets it on level 6; Lore Bards get more magic instead).
I also try to keep the Hag as merchant as long as possible to stock up on strength elixiers. They are really cheap and last all day, unless you die or use a different elixier. Running more than one character on strength elixiers is a PITA but running just one, and maybe occasionally boost the other warrior(s) in the group for especially hard encounters, is perfectly fine.
- Fighter and Cleric are both amazing pure class choices, even for ironman mode. I dont see much synergy between them though. Combining them will mainly delay both the good Fighter and Cleric features, and you will never get the third attack per action Fighter gets at level 11.
If you want to play a Battle Cleric, there is the War Domain. It gets extra attacks, though only a limited amount. AFAICS the really OP choice for Domain seems to be Light though, also thanks to itemization:
https://bg3.wiki/wiki/Luminous_Armour - with the right item choices, Light can shut down whole encounters on their own later.
Fighter has synergies with other classes, namely Barbarian and/or Rogue. And you can always add 2-3 levels of Fighter to really any warrior class for Action Surge and possibly some initial Battle Master or Champion features. However initially you want to play all warriror classes as pure class so you get to having the second attack ASAP - the second attack is a huge powerup.
Cleric doesnt really have synergies with other classes. You can add one level of Wizard to get a Cleric/Wizard pretty much as we had it in BG1/BG2. This is because 1. Wizard can learn spells from scrolls and 2. The number and level of spells only depends upon the spellcaster level, and both Wizard and Cleric are full spellcasters and give you a spellcaster level for each level. Other than that I think one should keep Clerics pure class.
- Keep playing monk, really. Its a great class, also thanks to itemization. You unfortunately locked yourself out of one of their best items by not buying the Returning Pike +1 from the merchant in the goblin camp. Its never equipped; whenever you need a ranged attack, you just keep it in the inventory and throw it when you need a ranged attack, and unequip it after the battle to get your unarmed melee attacks back.
You can just throw javelins instead though, just remember to collect them after the battle. Thats what I do on my second warrior anyway.
There is another thrown weapon later[1], but you either need to play as dwarf or have the Disguise Self ritual spell to turn yourself into a dwarf to use it.
- If you really want to change your class, you can use Withers. You cant change race and "body type" (aka gender) or name or racial features you picked (like the extra skill proficiency of humans or the wizard cantrip for High Elves), but you can change the class around as you wish.
[1]: I meant RETURNING. You can throw all kinds of stuff in this game, including all weapons, but very few of them magically return after throwing.
