So everyone knows the hot meme combos going on with Tapu Koko leads but I honestly feel that Koko won't be the tip top tap. Here's the "problem" I have with it: It's too fast. Its terrain will be overwritten by any other Tapu that switches in on the same turn. Granted the terrain's not all it brings to the table but many of the calcs I've been seeing (not in this thread but in general) operate under the assumption he will have electric terrain which isn't necessarily a given when it's in a lead role as many people seem to be wanting to play it, alongside Pelliper, Raichu A or Politoed. Lele is probably the 2nd most scrutinized for its anti-priority properties, a lead combo immune to fake out is obviously very strong anti-lead in VGC (leading Lele in fact simply shuts down Raichu A by taking both its fake out and surge surfer away).
BUT even slower than Lele, and negating her weather, is Fini and slower yet is Bulu. So you can't try to anti-lead with Lele without worrying about getting your terrain trumped and losing priority protection. The only Tapu who can actually assume he will always have his terrain down in a lead position is Bulu, who as some have noted has a wood hammer capable of some truly terrific damage with grassy boost (it can threaten an OHKO on most Chomp sets for example). Someone in the SM forum brought up the synergy between Bulu and Incineroar as a lead combo as well. Leading with Bulu or Fini has the added effect of preventing any attempts to counter FO with Lele. Some times slow and steady does win the race, at least in the wild world of weather wars.
Another thing worth noting is that the research thread has confirmed that Tapu Fini's misty terrain now works against confusion, and Tapu Fini gets swagger. This will likely allow it to give its ally a confusion free +2 atk which doesn't depend on an item slot unlike older lum/persim swagstrats. This, combined with solid bulk, good defensive typing, decent special attack, muddy water and of course the burn/paralysis/sleep immunity, makes Fini an interesting support choice for many physical attackers.