There's so much debate about this : I know from Motorcycles : My batteries last longer living in The North of Michigan then they lasted living in Florida for 10 years : Same goes for the Car. I've seen comments that batteries on E-Bike Drain faster in Colder weather :
Unless you have alot of experience riding in Cold Weather You shouldn't be adding to Internet Unfounded Gossip.
Besides When you say Winter Months : How long you going to be out riding in 20 Degrees : Likely you'll be riding Shorter or riding in days of upper 30's and 40's >
I wouldn't leave a battery out in the cold or heat for extended periods : Other then that I doubt you'll deplete your battery that much differently then in Mid Summer Hot days
As for All Season all around I personally am looking at Hardtail EMTB's Something like a Power Fly 5 or Specialized Levo or Cube along those lines : Were I to find a Deal on a full Suspension I wouldn't hesitate
MAYBE LIKE THIS (Gen4 Bosch Motor)
https://shopsandiegoflyrides.com/co...products/2020-na-cube-reaction-hybrid-pro-500
If you can't test Ride something I would find a place close to you that does this New computer generated fitting : Comfort is directly connected to Geometry: I learned that the hard Way when I started to Ride Regular Bikes again. Fit to the degree you can be fit without a Pure Custom made Bike is Important :