Are these leather boot issues fix-able by a cobbler?

I just got a pair of boots on EBay and the seller’s measurements were way off. The sole is an inch narrower, the shaft height is 2” longer, and the top opening is 1.5” smaller. This all adds up to the difference between a shoe that fits and one that does not.

How much can one stretch leather without damaging it? My toes and calves want a little more room. How much does it cost to have the shaft height reduced? Do people typically wear socks with boots? I imagine this is a nice thing to be able to do?