Yes it can.
0.8 inches.
I tried to fit the chains for a 215/70R15 on a 215/60R15, and the chains were too large. I suspect in your case the chains will be too small.
40 psi
It usually can
If they have the identical aspect ratio and wheel diameter as comparing a 215/70-15 to a 205/70-15 the 215 tire will be .56" taller.
235/60-15 or 215/65-15 are both acceptable swaps. I would go with the 215/65 as you may have clearance issues with the 235 series tire.
No, it will not.
Unlikely, it's MUCH wider.
No, it will not.
Yes, that is a very common change
Yes, the 65 tire is only slightly taller.