So I would focus on ensuring your system is capable of finishing at whatever higher resolution and application your are choosing to work in. If it handles that, then offline at DNxHD 36 will mostly likely be fine.
Blackmagic and AJA are supported with Media Composer. You will find a lot of forums discussing each. In the end, AJA seems to be more stable, but if you are using Resolve in your workflow then you will need to go Blackmagic. Finishing also entails proper color management and calibration – not only for the monitor, but the environment as well.
I recommend that audio syncing be done in Media Composer and not in third party dailies systems. Keep in mind if you want to sync to 1/4 frame accuracy you will need to create a with 35mm/4-perf project type and import audio directly.
If shooting ProRes, you will most likely be shooting ARRI Log-C so decide whether the LUT is baked in during dailies, or you will apply in editorial. Also, what aspect ratio will your final delivery be in?
Michael