Well, they launched an Avengers post-Secret Wars preview on Free Comic Book Day and being honest, those are the same characters from the mainverse but with Miles included. So yeah, even though it's a multiverse reboot, unlike what DC does I'm sure most 616 characters will stay the same.
Off the top of my head, the only hero characters I
really care about are:
Peter Parker, Miguel O' Hara, Miles
Storm, Night Crawler, Black Panther
Dare Devil, Luke Cage and Iron Fist
The Thing,Rouge, Captain Marvel, Iron-Man, The Punisher.
Sue and the Human Torch are alright too I guess.
Most of them are alive so far.
The OG Wolverine already got axed off. But the way he dies is really reverse-able. X-23 I think is taking over the namesake, which makes sense. Still not a huge fan of the replacements taking up a crap-ton of space, but at least it's a character that's somewhat reasonable.