Also, on the topic of Leech Seed Tapu Bulu, this is a set I created - or at least, I haven't copied it from anywhere; I'm not aware of this set being a thing.
Tapu Bulu @ Rocky Helmet
Ability: Grassy Surge
EVs: 232 HP / 180 Def / 96 Spe
Impish Nature
- Leech Seed
- Toxic
- Horn Leech
- Nature's Madness
speed here is for crawdaunt, horn leech is for stab and even more longevity. hp and defense are for ensuring urshifu only 4hkos. some spdef might be useful to mess with koko as well, but i guess it depends on team structure. the combination of rocky helmet, toxic, leech seed and nature's madness is a real pain to deal with for any common switchin. also, this tapu bulu has boosted defensive utility against stuff like zeraora, shifu, chomp without fire fang and lando, the aforementioned crawdaunt, rillaboom, kartana to an extent and even opposing tapu bulu. if you want to experiment with leech seed bulu i figured it could be useful to share this version. i don't know if its any good as i haven't tried it yet, but it could be worth a shot.