Q: What are the charging limitations/your recommendations regarding using Li in environments where it gets below freezing?
A: Do not install lithium batteries where they might get below freezing. They do have enough mass that a frosty night will not get them too cold, so long as it is warmer during the day.
Q: Can you run a Lynk LiPO4 battery bank in parallel with a lead acid battery bank?
A: Definitely not. I’ve thought that there could possibly be a justification for an inverter that could switch between the two, but I am not holding my breath to see one made. The lithium battery is for daily cycling and the lead battery is for backup only. I run two separate inverter systems and circuits to do so, but that is probably not applicable to many jobs.