Last two points could be debated.
Veganism isn't my choice, but a plant / whole food diet has been proven to be quite healthy. And if we are to believe the bible (if you do) it's God's original diet.
And as an Adventist, I can tell you for a fact...The blue zone of Loma Linda, California has very little meat being consumed.
I can say that everyone is different and their bodies require different things. I know some vegans that are in great shape, but they have to supplement almost everything like amino acids, etc. I know it made me feel weak when I tried.