Pretty nice work. Careful with crossed voices; it confuses the ear because of the shifting timbres trying to go to different places. Also be careful of unison resolutions for the same reasons. I know it's hard with 3 monophonic instruments but try to not to leave the 3rd out of chords if possible, unless it's a really intense spot where 3 third defines the mood too much, though I don't see it happening much here.; the fifth can go instead, if need be.
I would have also liked to see the building chords idea from the beginning, but I guess it's not super necessary. Nice stuff.