Is the Evangelion Remake a remake or a sequel?
It's interpretation. 

There's nothing official whether there is a sequel or not. Aside from Kaworu saying weird stuff about "next time" or "this time" (and a weird translation of Kaworu's voice actor mentioning something about "looping" in an interview), all of the other instances (including the large chalk outline) of possible "time looping" or "rebooting the universe" have been explained in-universe or through story-boards in a way unrelated to any sort of sequel, "time looping" or "rebooting". This is not to say such images aren't meant to make people think that, or at the very least, as a reference or a nod to the original series.


The seas are red as a result of second impact.
The chalk outline is from an accident before second impact.
The blood stain on the moon, also from second impact
Second impact in this universe occurs chronologically as the same Second impact in the original series (Antarctica expedition, Misato's dad dies, releases of Adam(s))
Kaworu saying stuff about "next time" and "this time", unexplained


Kaworu has always been saying weird stuff, even in the original series, or, perhaps he's the time-travelling wizard in this version of Evangelion. It's up to your interpretation, and there's a lot of ways to interpret things, especially since we've been given such all encompassing world changing events like Instrumentality, of which we know next to nothing when it comes to the details or mechanics.