Quick Volt questions if you don't mind

I'm sorry I haven't read through to see where the appropriate place to post might be. I feel in "crisis mode" - although I have to laugh at myself (first world problems).

I had my heart set on a Tesla Model 3. So much so that I pretty much ignored or dismissed other possibilities. The big 'reveal' was tonight and I was sorely disappointed. I remember the Volt was probably my #2 choice (although distant). I'm wondering if you wouldn't mind providing some insight that I can't really look up with facts and figures.

#1 - I live in a mountainous region. Long steep grades (8.5% - so not insane, but significant) and high speeds (120kph / 75mph). When the electric range is used up, how is this thing in the hills? I drive a Honda Fit now and it is woefully underpowered and I often can't hold the speed limit. More bothersome, however, is how bloody loud it is from the engine noise. That's a main reason I wanted a BEV.

#2 - It is listed as having a tiny 10.5 cubic foot cargo space... surely it isn't really that little, is it? When the seats are folded, etc... can you make a trip to Costco of any significance? Or is it as useless in that regard as the specs indicate?

#3 - How is it for tall guys? I'm 6'4, mostly in the legs. For anyone that's driven a Honda Fit... that's about as tight as I can go. I wouldn't call it comfortable, but I manage.

#4 - One problem with the Fit is that my kid... er... no longer "fits" (pun avoided as best as I could). He's 5 and still in a child seat and he's getting cramped. Again, can anyone relate to the Fit?

I'm really hoping someone's got experience with both the Volt and the Fit and can advise if I'm looking at a significant upgrade or not.

Thanks so much.