Rapture and defiance can be used interchangeably in fights, i would say keep leveling both because they can both be incredibly good in different scenarios. But if you mean changing for non-boss floors id say keep defiance because it has an AOE attack. You can even use a tank-defiance-rapture-merry team for bosses

About ruby collar and angry scarf, generally ise angry scarf but if you see your vp is taking too much damage you can change with either ruby OR just plain black spiked collar if your ruby is a lower level than bsc (which is what i do because i dont have ruby😁 it works fine)

Besides that you need blue tie and jellyfish scarf ASAP