Q1: Volume 3 part 1 (a.k.a. volume 3A) has been digitized and reissued as a paperback by Cambridge UP, see Amazon. The digital version is online in the HathiTrust digital library, but with limited "search only" access because of copyright restrictions.
With some further search I actually found a library in India that has placed the digital version online (a 54 MB download). Quite possibly not fully legal, but in the spirit of the National Emergency Library I guess in these times a download can be justified.