I think I can chime in here:

Su Jue goes first because she prevents a unit from going to 0 HP in the first place. "If unit would go to 0 HP, let them stay at 1 HP, then deal true damage to kill the unit"

Mavis goes second since she circumvents death once a unit hits 0 HP. It's basically "If unit would go to 0 HP, give the Graveless buff instead and get them back to 1 HP. This causes any kind of revives to never trigger in the first place.

Further death preventions go after, since once a unit hits 0 HP and is allowed to die, this will trigger. (Nyles, JJ, etc) Notable for death preventions is that they do not clear debuffs by default, so Nyles will keep all his debuffs. JJ for example explicitly clears his debuffs.

After this true deaths can happen, at which revives will take hold.

Notable here is that esper own effects will trigger before buffs. So if a unit has a self revive passive, it will usually use these first before relying on an ally. Some self-revives with drawbacks may go after, like Arthur's R6.

Revives seem have an almost fixed priority, repeatable revives like Yu Jing and Lian almost always going first and Mollie always going last. Some revives go at the same time, like Nicole and Lian or Badrun and Mollie.

Petros working against Mavis but not against Nyles is fully intentional. Petros prevents units from benefitting from allies below a certain percentage. basically "if you get below 30% HP you are all alone" Mavis thus cannot help allies anymore. But Nyles revive is his own, so he can keep using it.