Sorry, I was recording all day yesterday so just getting caught up here. For the brass stuff, I guess it depends a bit on what sort of feel you want. I would probably be inclined to introduce some more blues-based harmony to get a more gospel-y feel. A few random comments:
m22 - NP plays the 16th on 4 short, but real brass players will not unless you add a staccato. You obviously may know this, but wasn’t sure if you were going off the audio or the notation.
I generally would put articulations on any quarter that isn’t under a slur. At this tempo, there are too many options of how to phrase them, and you’re likely going to waste rehearsal time with the lead player dictating phrasing and everyone else penciling it in.
m39-40 - Could be a nice moment to feature the brass with even more interesting harmony, or more interesting melodic line leading into 41. Some more blues-based harmony could be nice on the blue note. Odd voice crossing with the Horn playing a Bb over the A in Tpt 1. If keeping this phrase and the Hn is col Tbn 1 for beats 3 & 4, I’d go ahead and double on beat 2 as well.
m47-48 - cues probably unnecessary (as Mark said above)
m49-56 - Long notes like these are physically taxing for the brass. Obviously fine for this piece, but if they are playing an hour long service or something, it might not be worth wearing them out with “footballs” unnecessarily, so they still have chops for the end of the gig. Just something to consider based on what else they have to play.
m60 - Could possibly make the modulation a little less abrupt by going from Cm to Ab7 on beat 3, then Cb/Db in m61.
m69 - Echoing Mark’s comments here. I agree that the blue note isn’t quite working, but I think it’s the voicing you have. Using a Gb7+9 there in the brass will give you both the blue note and the 3rd, which will then work fine with the vocalists. (You’ll need to put an Fb in there somewhere too.) Beat 4 isn’t working for me either. Fb triad over Bb? Minor 9th crunch between Tuba and Euph seems strange without any intervening notes.
m69-77ish - I kept wanting to hear some sort of deceptive cadence in here for at least one of the Gb chords. Maybe go to Ebm or something for one of them. (And a preceding Bb7 could be a nice harmonic change)
m79 - Could be nice to have a resolution on the last 2 chords instead of just repeated. E9 to Gb could be one option.
Overall, pretty nice writing though!!!