It seems to me that compatibility with FamiStudio (exporting in FamiTracker TXT mode) should really be improved. It says here that the volume data column simply "isn't supported".The two things you mentioned probably aren't supported in NESmaker's sound driver.
Check the txt file on this website to see what I mean: https://nerdboard.nl/ftm/
After that, import the txt file into FamiTracker and fix it up as the page says. Re-export the txt file and repeat the check before importing into NESmaker.
Eventually you'll realise that if you're gonna have to keep fixing songs in FamiTracker every time, you might as well use that instead of FamiStudio.
It seems to me that compatibility with FamiStudio (exporting in FamiTracker TXT mode) should really be improved. It says here that the volume data column simply "isn't supported".
Only volume, arpeggio, pitch, and duty/noise macros (the parameters in the instrument editor) are supported in the sound driver.
Read CutterCross' excellent guide for more details: The Definitive Guide to Composing NESmaker-Compatible Music and Sound
The NESmaker team was working on a music tool which would run within NESmaker, but then FamiStudio was released and they went "oh let's just use this instead of wasting our time making something inferior to this". (Not a bad choice considering how atrocious their codebase & UI/UX design is sometimes.) The issue is, the sound driver was originally made with FamiTracker's instrument-based workflow in mind, not FamiStudio's.