I have the PS4 version of Skyrim Special Edition and was using a mod that made most essentially npcs killable. I believe NPCs key to the storyline were still supposed to be immune, but apparently not Frea; she died in combat infiltrating Miraak's tomb. (Needless to say, I have since uninstalled the mod lol). I unfortunately didn't even realize she was essential until I got to the end of the tomb, at which point, I did not have a save point that existed prior to her death.

Now the Miraak quest line is stuck on "Talk to Frea", who is just a corpse and cannot be talked to! Is there any possible way to fix this? I wonder if there is either some reanimation spell or some mod that would be able to fix this issue, or if that quest line will simply have to remain broken for this playthrough... Any ideas?

Tell me you just got an old Save? That's the easiest way to do it.

There's a mod like that on X1, but not sure about PS4 (It's called Cheat Room, which I think can revive NPCs).

Unfortunately I do not have an old save lol, which is very surprising, because I realized this was an issue ~30 minutes after she died. Even autosave did not go back far enough

Hopefully the Cheat Room is available on PS4, it looks like your only hope at the moment...