To answer your "is it 4k or not" question. Arrow scanned the original 35mm negative to 4k, but released it onto Blu-ray (so 1080p).

Although if you really want it on 4k, I'd say to hold on for a bit.

It is speculative, but I'd say a 4k release is coming from Arrow in the near feature (possibly even this year).

The collection set, and single release have been discounted a lot, they've been re-releasing films to 4k, they have a 4k scan, 4k releases are coming out in other countries (November of this year in French for instance), and probably the biggest hint was Arrow's 'tease' from earlier this year mentioning "RC" (possibly meaning Ringu Collection).