The leaderboard is intended for full game runs. However, there's nothing to stop you speedrunning it, and there is already a community of people competing for both All Treasures All Castaways (ATAC) and for 1500 sparklium (Demo Any%)! If you want to check out previous runs, the best place is #Pikmin4 in the Pikmin Speedrunning Discord.
I'm going to guess there will be three main categories-
Cure Olimar
All Castaways, Treasures and Onions
All Missions
Probably one more with takeoff. You don’t need all the treasures, just castaways, so you wouldn’t have to farm for 100 purples nor would you need any of the extra onions. Probably would be called all main missions
Basically-
Cure Olimar-any%
Cure Oatchi-any%+
Cure all Leaflings-not sure if it should be its own category
RTONE would be vanilla 100% in my opinion
I don’t think Shipwreck Tale or the Dandori games would count, as they’re more their own thing, but every Dandori needs to be played anyway to get 100% in each level
Then of course there’s All Sidequests-I could be wrong but some of them loop over and over again with no clear end, but there are specific objectives like building every structure, filling out the Piklopedia and purchasing every upgrade