I noticed that some runs on the All Jumpscares leaderboard use the Death Coin. I'm assuming you're only allowed to use a Death Coin on a character you've already been jumpscared by during the run, but is there a limit on how many times you can use a Death Coin to get rid of a character DD has re-added? Or can you only DC characters you forgot to remove after getting their jumpscare/effect? Thinking of incorporating DC into my future runs to try and save time.

There's no limit on how many times you can use the Death Coin, you can use it as many times as you want on whoever is susceptible. But, if DD adds a character you have to get their jumpscare before you can Death Coin them. There's only 4 characters that DD can add that can also be Death Coined, so you wont be able to do this often. If you're having trouble with DD, I would reccommend both being aware of animatronics who can end the night before DD has time to add an animatronic, and to make more use of DD repels.

So, just to make sure I have this right:

You can DC anybody who can be taken out with the DC, as long as they haven't been re-added by DD. If they get re-added by DD, you then have to remove them by being jumpscared by them. Is that correct? Also, does that mean that if you never get jumpscared by a certain character because you DCed them and DD never brought them back, then you never have to see their jumpscare during a run?

The jumpscare of the animatronic must happen before you can death coin them, so, for example, you have to get jumpscared by Toy Freddy first then you can Death Coin him. If he gets re-added by DD then you have to get his jumpscare again before you can use the Death Coin on him again. This applies to all of the animatronics.

Sorry I didn't make this as clear as I should've in the first place.

That's okay, I'm fairly new to speedrunning this category, so it wasn't until I watched your WR run that I found out DCing a character is faster than manually removing them in the AI menu.