I'll answer as best I can, but I encourage everyone who wants to be up to date on this to check out the here now and just back thread:
https://www.disboards.com/threads/h...g-experiences-including-park-hopping.3807247/
1. Generally speaking, yes, they are all opening about that early. Each day can vary slightly, but this has become the norm.
2. For the most part, yes, but people are reporting showing up 75-90 minutes early (before official park opening) to be first in line or near first in line for the bus. Remember, reduced capacity bus could mean longer waits to get to the park.
3. In most cases, and again, this varies by day, the headline attractions in each park are opening before sometime during the early opening time.
HS - MMRR, SDD, mfsr, tot, rncc, RotR have all seen early openings, though the first 3 are usually more consistent.
AK - Pandora rides are usually open early, not sure about any others.
Epcot - test track, Frozen, and Soarin I believe have opened early, not sure of others.
MK - mostly just 7dmt and PPF.
The link I shared has reports almost daily from people in the parks detailing their experience for the day, so as your trip gets closer, it helps to check in and see what's changed or currently happening at park opening including unofficial opening, transportation, and rides that were available pre-official opening if they were there for that.