Very nice to see such a detailed review here in the comments. Thank You!
It's pretty surprising to me that we are getting comments about great coherency, while our music styles, tastes and generally preferred frequency ranges totally differ (PebbleWheat manages to pull off much better use of higher frequencies, while I tend to be very timid with highs).
It's also nice to see someone else trying to collab, I will definitely give Your submission a listen.
As for what helped to bring our vibes together, we first of all had a discussion on what musical style do each of us wanna go for, what is the backstory, style of the story. Then we have discussed what reference tracks are we planning for each of our tracks. In other words, communicating with your fellow collaborator and writing down agreed ideas basically guarantees at least some sort of cohesion.
I sincerely encourage you to keep on trying, collaborating and keeping the passion for music alive! Peace, see ya!