Interesting to read this right now. (Bear with me, please.)
I'm currently on UN7 (PJ1 baseband) and doing some research on EmotionOS & Lineage (I'm just not all that satisfied with all the Samsung-related apps I never seem use on UN7, plus logcat issues and no working encryption). Prior to UN7, I was on CM -and as we all know, that ship has sunk and LineageOfficial isn't sporting an official build for the Note 4 (trltespr, or any for that matter). I was having issues with SMS/MMS and got sick of having to do the *#*#4636#*#*-thing. Fortunately, UN7 has a separate, flashable fix in Post #2 (
https://xdaforums.com/showpost.php?p=70551195&postcount=2) for the SMS.MMS issue. Although I'm still on UN7, it worked for me.
That said, I'm wondering if
@tx_dbs_tx 's fix could be used to resolve this issue (or at least serve as a model for resolving this issue).
Just a thought...