Absolutely. Before the fall and even afterwards up until the flood had wiped out all crops, it says very clearly that we were herbivores. I don't believe, from my reading of the Bible, that Christian salvation depends upon being vegan but I do believe very strongly that God would prefer it that way, and in the coming Kingdom, death will be eliminated and even "The lion will eat straw, like the Ox" (From Isaiah)
Exactly, if you take everything in context, veganism is encouraged. And we’re encouraged to eat a broad range of plants.
But I think it could still support fruitarianism. Fruit is clearly held in high regard. It could be that as we progress towards greater enlightenment, we’ll return to a fruit-based diet (like in the garden of Eden?).
I think we’re kind of splitting hairs by arguing about whether the Bible is for or against fruitarianism. The point is to be kind to other living things, yet also to do what is necessary to survive. That could be anything on the PB to fruitarian spectrum.