Verve by Dieter Steffman seems to have the most complete character set - created by him - his freeware fonts have been around for a long time and I would assume you are OK to use them for this purpose.

Yes Don Munson is the designer. More info in a note from J-Louise Heron in a conversation with philippe2 (phillipedada) in the Myfonts forum (May, 2005):
---start quote---
Don Munson, former Art Director of Ballantine Books, NYC -- designed MGB Patrician. (The initials I believe were for him, his wife and partner, the Patrician for his daughter) At first it was a typositor exclusive at Haber. They would bill out 2 dollars a letter for each letter they set. Eventually, it was turned over to Letraset and made a rub on transfer - with those great alternative "S"s...
Mr. Munson left his job - Haber’s shop moved into Image’s shop - and old man Haber, left the office one night - took 4 steps outside the door, had a heart attack, and was found dead on the floor later that night....
-- end quote --
MGB Patrician was published in the Letraset Product Manual with credit to MGB Communications Ltd.
There are several independent digitizations.
I would not use the Steffaman version as in my opinion it is a rip of digital outlines created by another font maker. Mr. Steffmann's practice was to "share" fonts to which he had added characters and did some tinkering. Such fonts are not really his work. I have examined a good many of his fonts and often have been able to identify the source of his rip.
Similarly Brendel's Aegina, and Opti's Protea are clones of each other (the old Chicken/Egg problem). Both of them have the same upper and lower case, with the swash caps and some other alternate glyphs in some very strange places (such as the trademark slot, etc.)
About the only digital M.G.B. Patrician legitimately available today that I can say with any confidence is an independent digitization of the Dan Munson design, is Mazema by James Harris http://creativemarket.com/harristype/90257-Mazama-Regular.
You asked about "legally use."
As for legitimacy under intellectual property law, this varies from country to country. As you are located in the US, I will comment, as a non-lawyer, on the US rules. Digital outlines are protected under intellectual property law. The design of a font of type, in any form, can be protected for a limited number of years by applying for and receiving a design patent. AFAIK the design of M.G.B. Patrician was not patented. If you have concerns, don't take my word, but consult an IP lawyer.
Don

Excellent response, Don. Thank you very much for your input.

My 2 cents, James M. Harris published the Mazama in 1991 or 1992 - I am not sure - as shareware. The fee for actual use was then $25.