A fair bit of warning, but on the contrary ABC has been notoriously known to spoil deaths in promos for other shows before.
If there’s gonna be an ep where a main character dies, they’re gonna hype that in the promo for the ep it happens in, because killing off a main character isn’t the kind of promo gold they get to play with every day. So the fact that the promo for 315 mentioned nothing about a death, makes me really doubt that a main character is dying in 315.
IF someone dies in 315, IF the scene in 316 IS a funeral, I’ve been saying since we knew that Little John turned into a monkey that maybe he’ll end up being killed when he attacks people. And in the promo for 315, we’ve got a monkey attacking people. Death of a minor character like LJ wouldn’t be anything worth hyping in promo, it’d just be a thing to keep as a shocker when the ep airs. And if crew were telling fans that a death was filmed, maybe it was LJ’s death, and the crew were just trolling the fans, being sneaky with how much info they did or didn’t reveal when they said, “Oh yeah, the death has already been filmed.”
Basically, until the ep actually airs, we know nothing for sure. But I still believe that if a MAIN character is being killed off in an ep, they’d promote the crap outta that because a major death would likely draw in more viewers, so you don’t waste that opportunity by not mentioning it at all in the promo.