Hey LH, I’ll take a stab at your questions although there are so many variables that it’s hard to forsee all the permutations -
I found this website that seems to have some FAQs and specs specifically about the streaming requirements -
http://www.nbcolympics.com/watch-live
Based on what I see there and assuming Chrome is your preferred browser, it sounds like Adobe Flash would be the most significant add-in to update if it isn’t already up to date. Typically Chrome takes care of updating Flash, but it’s not unheard of for something to go wrong with that process occasionally. I think what you did with regard to Adobe Shockwave is fine but possibly not relevant (per the link). Both Flash and Shockwave are products that work with web browsers (and sometimes other software) to deliver interactive content.
If you subscribe to Dish for TV, it sounds like you should not need any kind of VPN - that only comes in if you don’t have a subscription to a service that is partnered with NBC. I found this info just now from Dish which appears to be new news as of yesterday
http://about.dish.com/press-release/products-and-services/dish-present-nbcuniversals-coverage-2016-rio-olympics-including-
To the best of my recollection from London, when I went to watch a live stream, I was prompted to put in my Comcast creds - therefore there was some kind of authentication between the streaming app/site and my provider that determined that I was good to go. I have no idea how that was determined or controlled - thankfully, it worked.
Hope this helps at least a little!