For further explainations check the guides here on speedrun.com ... they are very helpful :)

Humanity dupe happens in the firelink elevator, the bells are the things that you ring after quelaag and gargoyles and wrong warp is the way to teleport to gwyn by using a glitch.

Of the gate barrier is still there, try to do the skip on the other side of the bridge. Sometimes NPC and gate hitboxes still load on switch for some reasons. Happened to me before. But still: go for duping and bells first to save time.

You can't prompt swap on Switch, so no PCC wrong warp. That means, if you wanna run any%, No Wrong Warp will be the route, except the meme rolls (Dukes Elevator old skip etc) Also: IGT in 30fps runs faster and you got longer black screens ... Good Luck