Where can a Chaplain candidate in the National Guard find clear guidance on promotion from 2LT to 1LT?

To anyone in the same boat, the reserves, and the national guard have Chaplain Candidates AD does not. Long story short, if you are a Chaplain Candidate you must complete CHBOLC BEFORE YOU CAN PROMOTE, if you are AD then this does not apply.

It sound like you received your guidance, but here as some experiences/thoughts (can't guarantee 100% right, but I believe it is pretty close). As you likely know, CH is a specialty branch, so there are separate promotions boards (so you competing against other Chaplains rather than all officers in your grade). Something a little unique about the NG are separate state-level vacancy promotion boards. This will apply later more in your career, but if you are serving in a higher-rated position and have the minimum TIG, you can be promoted into a position 'vacancy' for the next higher rank. This is similar to regular army below-the-zone promotions in some ways. Otherwise, you would need to wait until the HRC army promotion boards for AR/NG Chaplains comes out (once a year I believe), at which point you would be looked at along with all other RC chaplains.

It's essentially the same with most MOSs (especially specialty branches). Time in grade (TIG), MOSQ, degree completion all come into play. Basically if you have MDiv but not MOSQ you're 1LT. No MDiv and not MOSQ you're assessed 2LT. MDiv and MOSQ you're assessed 1LT or CPT. Appears you have your answer but if you're not sure then either respond back, talk to Spec Branch Recruiting (since they control your packet) or you state/FT support Chaplain. AR 165-1 mostly explain activities not personnel management. DACH-PER is where you need to get more detailed info.