Yes you can use NREM to be conscious through all night. I do that sometimes. It’s a nice tricky technique.
I think NREM as my opportunity to take a break and reenter when REM cycle begins again. You also sometimes can dream in NREM too. So, keep that in your mind when you’re conscious… just don’t move. Be very still and you’re mostly likely to jump back into REM as I call it, re-entering technique. It is useful if your dream ends prematurely and that you happen to stay in this deep NREM stage… you always can re-enter. You know what I’m saying? 
Anyways, to OBE in this level of NREM, there are many different techniques for that. Let me refer you to The BIG OBE topic part II. It has many good information. You also might want to look in part 1 too. It’s the common way… OBE’ing from NREM stage (or even REM stage too).
Hope I’m making sense here. 