I don't know the answer to your question, but I truly hope some knowledgeable devs take an interest in improving verizon compatibility (not likely Verizon or OnePlus will do much).
Getting volte working might not be possible. But, getting the device to listen for CS events (voice, sms, and mms) while staying connected to LTE seems more doable. I mean not doable by me, doable by someone who knows this sh!t
