Love the description in those muddy fox tights - padded undercarriage
I find taking a leak in bibs fine, easier with a zip or low front, but even.with a high front, where there's s will there's a way, and I find the benefits of warmth and no waist compression far outweigh inconvenience.
It's taken me years to get to a cosy set up, but I'm pretty much there:
Dhb bib tights - padded
Helly Hansen 'warm' base layer
Cycle shorts over the top with pad cut out or no pad
Endura windchill windproof jacket
Merino socks
Normal bike shoes
Endura lumilite overshoes
Endura dexter gloves
Very thin cheap decathlon gloves under the above for Baltic road use
buff under the helmet when sub zero