Hi, it takes place in the same region as the other part IV's Celceta. as for the actually story, plot were still not sure how much will remain since there is really little info out as of yet. As for the gameplay however it seems like a complete reinvisionment and based on Ys 7 and not like the Chronicles and Felghana remakes
Chronicles wasn't a complete remake, rather it was a mildly enhanced PSP port of the PC games Ys I and II Complete which were themselves mild updates of Ys I and II Eternal, which actually were extensive remakes. Oath on the other hand was a bottom-up remake and that's what this game is going to be as well.
Also, it takes place in the same region (Celceta) as every other version of IV. In fact, it's right there in the title of the remake. We can also see a couple recognizable things in the artwork and on the map in the trailer (the tower and crater respectively). That being said, Celceta is clearly being expanded a lot and the actual story is probably going to be quite a bit different for a number of reasons.
Now, one thing that might change is the Esteria segments. Ys IV makes huge references back to the events of Ys I and II and as an extension of that, Mask of the Sun and Dawn of Ys both have sections where Adol returns to Esteria and explores around (Lilia and Goban both feature rather heavily). Falcom may or may not decide to keep that in their own version of the story.