Hello Rafael, I can offer my experience with a couple of your questions:
1 - We have both goats and Llamas. From reading, the Llama manure seems best by the numbers, and is certainly easiest to collect as our Llama always goes to one of a few spots in the pasture to deposit it.(very easy to shovel into buckets) For years we used it directly into the soil without any composting with no negative issues. We currently have a certification that requires us to compost it for 120 days, so thats what we do. We also use our goat droppings but in a much more indirect method of just letting them graze our food forest areas and deposit them everywhere.
3 - We eat animals because I prefer knowing where my meat comes from, this is of course a personal decision.
4 - We shave our llamas for health/heat purposes but have yet to spin yarn out of it, but that is on our to-do list! We shear every year just so he doesn't get too hot, we are in zone 6 and have a few 90F+ degree summer days.
5 - Hard question to answer, would vary by animal species, plant growth rates etc... Im probably the wrong person to comment on this because we load our land very lightly. (we have a dozen or so goats, a llama, ducks and chickens on 15 acres) But we practice paddock rotation so they never spend much time in one place.
6 - Goats will browse a variety of plants, for ours anyway grass is not on the top of their list, they seem to prefer bushes/trees, but they certainly eat grass too. Our llama eats almost exclusively grass/herbacious plants. Im so glad you asked about Llama packing, our male can carry 80-ish pounds all day long, anywhere we can walk he can walk, in fact he walks many places we would rather not (up steep hills, etc...) Our llama has a personality sort of like a cat, he doesn't dislike people but he really does care if we worked with him or not. He is content to just walk around an eat, not as affectionate as our goats.
Hope this helps some!
edited for spelling