Sure, maybe. I don't know from what I understand is that the dude that made SH fucked off to Sony Japan(before it was cucked) then he essentially made a really flawed survival horror game called Forbidden Siren, this game you really need a guide to complete it.
While the co-writers, programmers and producers just tried to figure out what to do next then they started to think of deep themes they wanted to have in the game.
So in that sense, yeah one can say it is like going back to 1 but that is, if you only play it once, then you will even believe it has nothing to do with the cult or explains any lore, while the game explains more than you'd expect and at the same time gives you an understanding of the spiritual power that got corrupted.
Most likely, yes. It is made by the Polish development team called Bloober Team that brought you classics such as Observer, Layers of Fear 1 and 2, Blair Witch and The Medium. Since they are the only Indie devs that have been somewhat successful of having a niche of mostly FPS horror puzzle games, they believe(I shit you not) that they are going to make the next classic Silent Hill game which is already based of a classic game, I think they are really delusional because The Medium was good but it wasn't even near a survival horror game standard like the RE numakes or at-least 2.
SH4 had a generally bad development to begin with, so they put inn elements of SH lore and stuff. In general it is the best outside the trilogy because they at-least knew what was what with Silent Hill.
Because in SH4 they kinda establish that that Sullivan is a plan b, if she cannot birth the god.But that also means how could the cult know that she would split her soul?
Because it took about 17 year later with the end of SH1 for the new God to start to be reborn when she gets despair and anger, obviously then the otherworld is getting birthed into reality when the god is birthed, while in the first one the otherworld is invading the reality.
Now when it comes to the canned Silent Hills, I am actually really happy that Kojima didn't sully the good name of SH(even when more than half the series hasn't been good) but now I am excited for the new Silent Hill F, I believe that it can be a real mindblowing game because the writer is behind When they Cry, it is a mindfuck of a visual novel and to get a nice grip of who that dude is, just watch the anime When They Cry.