To answer some of your first few questions
Incoming calls – This is a new occurrence that I just noticed today. Phone was in my hand with no ring or vibration. I had just playing on the phone awaiting a text from someone else, and the VM icon show in the top tray. I check, and it’s my dad. I phone him and never get a ring. I power off my phone, restart and call back. He answers and said it never rang on his end – he just saw it come up with no ring. (It never rang for me either.) Since we’ve been dealing with this for a while, he just tried picking up when he saw it. It doesn’t occur on every call, but recently it’s been on every first call. Almost always when I call, I get no ring, but they do and pick up to answer, but can’t hear me. They call me back, and I may or may not get a ring. Ultimately it winds up working, and we get through (or we’ll just go through one of their cell phones).
It’s like chasing a ghost as far as diagnosing it from consistency. From work last week. I did get through on cell on first try, but not when I was on wi-fi. It’s frequent, but sporadic, and only unique to their home phone number as far as I know.
I checked (for each I have the home phone under contacts), and neither was set to go direct to VM. I am on a Moto G6. The plan is unlimited Talk & Text w/1GB data paid annually. I need to check if that occurs on my wife and each child’s phone, I guess. Same plan – but different phones. (BTW – just called them from my wife’s phone with no problem.)