What side quests/ boss fights are necessary to do before reaching act 3. i dont wanna miss out on anything. (act 2 spoilers below)

I have yet to defeat second sentinel, enraged conchfly, widow, broodmother

i have done the wish of collecting organs asked by the 2 dudes in sinners road, currently in process of learning vault keeper melody and doing the putrified ducts quest (collect various kinds of organs).

ive also dueled garmond and zaza, talked to the loam and got all the fleas from vog and moved all of em to putrified ducts.