I’d say the arse cream is an optional extra. I use it when I remember, I think there is marginally less soreness with than without.
Edit: Udderly Smooth is another gooch-creme that is cheaper than Assos and pretty good.
Bibs are fine for peeing, the fronts stretch down well enough. Advantages are increased comfort due to no restrictive waistband, this may not be an issue for you. Also the shorts stay up better at the back, again may or may not be an issue for you.
I find Gore to be a good combo of value and comfort. DHB from wiggle use a very similar pad to Gore and are typically cheaper, but I can’t get on with their sizing so don’t use them unless they are the last clean shorts in the drawer.