Amazon is now listing this formerly-solicited-and-then-cancelled TPB collection with a new publication date of September 26, 2017. None of the prior solicitations for this title that I'd seen in the past ever showed an actual cover for the proposed collection, which makes it seem especially nebulous. Generally, solicitations will have at least a "Not Final Cover" disclaimer over an image if the actual publication date is too far away for the cover to have been definitely decided upon. This solicitation on Amazon (as with all previous solicitations for this title) merely shows the cover to ARCHIE & FRIENDS #146, the first part of a 2-part "Twilight" parody story (Part 2 was in A&F #147), so we can conclude that that 2-parter forms the centerpiece of this them collection. It seems likely that any B&V vampire-themed collection would also reprint the 2-parter from BETTY & VERONICA #261-262 (the 'Betty the Vampire-Slayer vs. Vamperonica' storyline).

You have to wonder why they'd use the cover from A&F #146 though, since the TPB is titled as a B&V collection and Betty doesn't even appear on that cover, and there's just 'something' about the title "BETTY & VERONICA: LOVE AT FIRST BITE" that seems a little too innuendo-ish in its possible implications to begin with.

Anyway, here's the listing on Amazon if anyone's interested in pre-ordering this. The worst thing that could happen would be... nothing at all.
https://www.amazon.com/gp/product/1619889463/ref=pe_11480_217674830_emwa_email_title_1