So after having played both the original game and the Platinum Hits over the course of my life, there are several "quality of life" changes between the two versions the game, most of which make the game easier to speedrun. The notable changes from the original to the PH version include:

-Water Slugs and Combustasaurs require only 6 hits rather than 10 before transforming into that lizard thing

-No yellow Spikers show up until Everwinter (world 7)

-No pink Spikers show up until Forge of Hours (world 8 )

-There is no Tom-Tom Biker in Time Square: Stage 2

-Clothes are cheaper, meaning you can get the bright set at the end of the game and style hard on the final boss (assuming you have gold)

-The silver Cat Medal in 4-2 is a little harder to find, but doesn't require you to go out of your way to get it like in the normal version (useful for All Medals/100%)

In case there were any confusing bits in my videos, this should explain why my copy of the game may differ from any of yours and why I personally suggest that people run the PH version over the original. Aside from getting a little more gold in Time Square Stage 2 in the original version (even though you lose a lot more time at the beginning taking out the biker), I don't believe there's anything that the Greatest Hits version has over the normal version. Thoughts?

Including the final sweeper would mean that a ton of the end of any 100% run would involve grinding for a LOT of gold. Generally, even in a casual run where you buy as little as possible, you don't get more than 20,000 gold by the end of the game, so I'd agree with leaving it out.

I do like the rules you've suggested, though S+ on everything might be a bit hard to do since some stages need a bit more prep than usual to do it (and a bit more grinding for FFs too)

I just completed a new run that's something like 30 minutes faster than ny past ones (speaking of which, I'm back into the speedrunning after SGDQ piqued my interest quite a bit), so I can go back and provide IL times a bit later since I haven't deleted that file yet. There's a couple notable terrible ones though, if you include resetting the level (specifically the R5 boss and Everwinter Stage 2)