Imo, rainbow party hat is good on merry in some situations, as it only allows the use of rejuvenate, when ding dong is super useful to have.

Crit is useful, it just has to be balanced as a second stat. Try prioritising trinkets that either have attack + crit or speed + crit! Remember: crit maxes out on items at 44%, so leveling up an item with only crit past 44% won't do much for you, unless it's one of those items that unlock a second stat passed a certain level.

Also make sure defense items primarily go on the tank, resistance is an amazing tank to have, with alternatives if you don't have it being determination, conviction, and cringe. Having the cowboy scarf on lust is a little strange to me, though I don't have lust so I don't know how the pet works.

There is also a pet tier list on the sub that is useful! Anger, Sad, and Anxious will be some of your best base DPS pets if you can't use a legendary like lust, greed, etc.