On the subject of safety ...
A couple of years ago when I started thinking about a hybrid solution, I frequently heard the risk statement "you can't mix chemistries" because apparently bad things will happen. (I have a cartoon picture in my mind of a mad professor dropping lumps Lithium into sulphuric acid in a beaker producing lots of coloured smoke lol.)
I have never seen any explanation of what that actually means. What exactly is the worst bad thing that happens when you 'mix chemistries"? I would love to know.
There is an electrical interaction between the battery types, and it's important to understand how that can play out in worst-case scenarios. What else?
My safety assessment was focussed on risks which are peculiar to lithium and an interconnected hybrid architecture. There are plenty of risks with lead batteries which are also extant in lithium batteries. These are important, but are not reasons to discount LFP.