I have a medium size Silvertip, pretty much the same frame but with thin tires and faster gearing.
It has a decent hybrid seating posture so it would be good for commuting.
I've ridden on flat grass with no problems but it is worthless in sandy conditions, but my tires are only 35mm wide slicks.

Since the Bullhead has 2" tires it might be OK for Winter, but I'd seriously get studded tires if snow and ice are on the ground as you mentioned.

It's not a small fold but I think the Bullhead would endure crashes almost as well as a regular diamond frame.
Since it has standard (short seatpost and stem) components there isn't any greater risk of damaging them in a crash.
When you look at a regular folding frame like the Dahon Mu or even your Brompton, I wonder how well that long stem and seatpost would endure constant crashing.