About apps being dead (etc). It is true that some apps stop development, but the type of board it sounds like you are making isn't something that relies on a lot of third party marketplace apps. The official add-ons themselves, such as the gallery, blog system, and ip.content are all excellent products that I use on my site.
I have been an active customer/member of Invision Power for over two years now and any time that I have had an issue, the company has quickly helped me to resolve any problem.
Question - Would this system work with a livestream account? Instead of pulling videos from a specific forum, pulling videos from my livestream account would be AWESOME because the old ipb app that did this (iStream) has stopped development.
Start up a club and tell your members that part of being in the club is participating in the boards.
I know it sounds like a 4th grader technique, but I participate in an online gaming community and part of the requirement of membership is to show pride for your community and participate on the forums.
2) I think he is asking about your support response time. I can't answer exactly, but I do know that the IPS support team normally responds within a few hours based on previous experiences. The only time where this changes is during non-business hours, such as on Saturday/Sunday. Even then, during critical support issues in the past, I have had staff members help me on the weekends as I believe that some of the staff members check for tickets throughout.
If you already have a license and you are paying upgrade fees (ie if you are an active client), depending on what it is, something like 15 bucks every 6 months for certain programs, then upgrades are included and you just have to visit your client area to download them.
I'm pretty sure that you aren't supposed to touch the licensing message at the bottom. I can see how it wouldn't make a huge difference because it would still say invisionpower, but I don't think I would even push it and would rather keep it in place than make a mistake.