There are a lot of wonderful folks here and tons of helpful information! I have no doubt that giving this dietary style a shot will really open up a lot of cool stuff for you and help you with what you want to accomplish! If you can get the 80/10/10 diet at your local library, do it! If not, it's not cheap, like buying a hardback book, but it's a great reference with a lot of really good info!
Check it out, there is a lot of information there and will help you to have a better "lay of the land" here. From your posts I can see that you were wondering why there was some negative reaction, honestly I think most of that was to the person in the video and some of what he puts "out there".
But also, we are a high carb vegan support site, not a high carb vegan apologist site or a site where we debate the validity of a high carb vegan diet, that is already assumed.
Check out some of the links on that page I posted the link to and then scroll all the way up and use the little search box to do searches on supplements, vitamin D, B12, etc, and you should be able to find a lot of discussion that should help you with some of your questions about supplements, etc.
Again, welcome aboard, I'm sure once you see all the guidelines, etc a lot of the things will make better sense to you :)