1. Should be a rule to disable coin items (the items you get after filling your coin meter) since it adds a bit of rng to runs that could make getting world record tedious in the future

2. A Category for all levels in one sitting, would be a cool endurance run that would make mistakes have much higher stakes (Edit: Oops that alr exists)

Honestly using the default ruleset and custom ruleset should be separate categories

1. A bit of RNG is good in some speedruns, plus I can't think of much that would give coins an advantage.
2. That already exists

An example of coin rng being a huge benefit would be if you got the propeller mushroom right before a part that requires you to scale up a wall (which happened to me in a test run which is why I thought to post this suggestion) tho I think some rng is good in speedruns to have the most optimal one here you would have to hope you got a propeller mushroom when you hit 8/8 coins and there's no fun or skill to just rolling a dice

I think any type of Mario (or platforming) speedruns should focus more on platforming skill and optimization rather than having to rely on a dice roll part way into a run unless it's a glitch of some sort.

I think the no coin meter rule should apply to all categories