[HM666]

A) Is it possible to install this older version of VB in order to gain the functionality of this mod?

Yes its possible to install older version of vBulletin but I do not believe you have access to 3.6.2 and I would not recommend installing 3.6.2. Its not supported anymore and will not be updated or fixed/patched in the future more and likely.

B) Is this a safe, stable release of the VB software - or are there exploits which are well known?
Answered above.

C) Is there a more up-to-date version of this modification/hack that someone knows about that provides the core functionality ( Event Calendar with Email Reminders ) that runs on VB 4.2.2 or the like?

Here is a mod for 4.2 although I do not know if its buggy or not that is something you would have to read in the thread for yourself. https://vborg.vbsupport.ru/showthrea...ighlight=event

D) Any other thoughts, input or suggestions anyone might have to help me on my quest?

Finding a forum with a built in events feature that would probably suit your needs is most likely just not going to happen easily no matter what forum software you pick. For all forum software there are professionals & freelancers who code these types of things custom for clients all the time. Either way you go you will probably find that you will need someone to custom code this for you anyways so I suggest that you go with the software that you like the best that has the best functionality for your niche & site. Pick the software that you feel the most comfortable with and then pick yourself a PHP programmer to code your custom events module.