That’s not a basis for the choice. Basically it’s better to choose 64 bit if it works on your platform. https://www.digitaltrends.com/computing/32-bit-vs-64-bit-operating-systems/ or some similar result for 32 bit vs. 64 bit search.
Leave them as they are by default, just check out that the libraries are unchecked.
At the moment, yes, but v6 won’t work on Windows 7 because W7 is unsupported by MS, and for certain practical reasons. If you find a working solution for you, keep the installer package file safe. You may not be able to update to a later version.