Huayna Capac is the obvious choice...
But so far every time I took the obvious choice, the game played out completely differently.
So, Louis, you've got this. Culture. By whatever random date. Napoleon will probably grow large (although both Washington, with perhaps a decent amount of units, and Rameses, with an early unique unit, can cause Napoleon trouble - but Napoleon is usually one of the more solid warmongerers). Temujin is lucky to be put in a corner with a decent amount of land, but as with Napoleon, both Rameses and Charlemagne (Protective, and if not a good AI, at least also not a bad AI) could be surprisingly tough or otherwise delay Temujin for more than he would like. Charlemagne has the potential to peacefully grow large, and I would assume Charlemagne grows faster/larger than Louis does... But Louis is more reliable in the 'I'll sit in my corner and spam wonders for culture' kind of way, while Charlemagne can go on side quests with religions and units and all kinds of things not necessary for someone laser-focused on achieving a victory (but maybe necessary for whitstanding the Mongolian hordes, which Louis doesn't need to fear). Could Huayna kill Louis? I suppose yes. But again, the obvious choices have failed so far, so Louis, you've got this.
I don't trust Napoleon to come in second... Charlemagne it is. Whatever will happen to Huayna Capac? I have no clue (probably he kills Louis and comes in first, but then still Charlemagne would be second)!
Rameses is surrounded, but Washington will be first to die. Although I think the exact date of the first to die will be quite far in the game - if someone dies at all... You know what, I'll put in 'None'. Huayna Capac and Napoleon could take down Washington, but Washington could survive if it's only of the two attacking him, and that also applies for Rameses (switch 'Huayna Capac' for 'Temujin'). Every AI could survive to the end... And that's a fun random choice when I'm off the obvious path anyway.
Wars... Eight or seven. Eight feels likelier, so seven it is.
As for the date of victory... If Louis is left alone to spam wonders it should happen relatively fast (oh, you mean, put massive culture pressure on Huayna Capac leading to war and subsequent death? Oops). Turn 300, nicely round number.