There is currently a 75% resistance cap for everything. Elemental resistances usually have ways of getting that increased, temporarily or otherwise, such as fire resistance cap getting increased by Demon.
Physical Resistance will not be able to be increased past 75% and that'll probably apply to most enemies as well.
I don't think reaching 75% Physical resistance will be terribly easy either, or at least I will try to make it so.
The mods you listed -
All of them would probably be compatible.
Even reduced number bloat, if loaded after mine, would just override my numbers.
Randomness - No. No saving throws. Dodging is a thing but I don't think it's terribly difficult to get your chance to hit up to 100% by either reducing the enemies chance to dodge or your chance to hit. For CC effects the only RNG currently is an edge case involving Aptitude - If you cast a spell with 3 strength and you have 11 points in Aptitude, the strength will be increased by 10% up to 3.3. This translates to a strength of 3 with a 30% chance at a strength of 4.
RNG is something that I get asked about a fair bit but it's something I'm trying to break away from. That's one of the things I think Larian did right.
RNG in DOS1 was typically frustrating more than anything - Missing a 5% saving throw on a critical spell in the battle? In several cases during a DOS1 playthrough that meant the enemy was not CC'd the next turn and OTK'd my entire party, simply leading to a reload and try again. To me, having something with a 95% chance to hit doesn't create uncertainty, but rather takes something that I read as a certainty and has it fail.
I'd actually be more OK with a 50% chance for something to fail than a 5% chance, because the 50% chance you can rely on it to be unreliable. And if you can apply other statuses, potentially guarenteed ones, to make that 50% chance a 100% chance then you can turn the hail mary shots into something guarenteed with a few extra AP.
If people after my mod released still really want RNG such as that then it's going to have to come from another modder as an addon.