Since no-one has specifically answered your questions, I will tell you a little of what I know regarding Adobe and Vista 64. However, on their web-site, they are very clear about their Vista support so if you are depending on any feedback from this site, I would suggest that you re-examine your requirements (I have been badly burned in the past and strongly suggest that you go to the source).
I own Adobe Acrobat version 8 and it works great with all versions and 'bitness'es of Vista. I am currently using Vista 64, only. Vista 64 is not completely supported by Adobe (but I am a survivor... see Adobe's site). I have found through an Adobe user's forum that for Acrobat to properly work, sometime during its install process you will need to substitute a 32bit version of a standard dll for the requested 64-bit version (pdf.ddl_64 was manually renamed to pdf.ddl). After I made that one substitution, I have not had any issues with any of the Adobe products, 32-bit or 64-bit.
To restate, WRT to asking these kinds of questions regarding Adobe products... First, YMMV. Secondly, Adobe, MS, or even the dear old IRS of the USA is not your forgiving friend.