Hi Rafael,
I can respond to #2. We have both Nigerian Dwarf goats and East Friesian sheep that we milk and use the milk for personal consumption. We drink it, make ice cream, yogurt, kefir, cheese, use the whey for making bread, etc. My kids all love both the sheep and goat milk. We've tasted some pretty bad goat milk in the past and weren't sure we would like the goat milk, but it has surprised us... we LOVE it! The sheep milk seems to be higher in fat (very creamy and the cream separates faster than the goat milk) and seems to make a higher amount of cheese vs. the goat milk so we usually make our milk products out of the sheep milk and drink the goat milk. I say "seems" because we haven't measured or done anything scientific to prove it, but eyeballing it that is our experience (and may vary depending on what they are eating or our particular animals). However, I must put in here, that once the sheep were adjusted to the forage here (as opposed to their former home) we have had zero problems with them. They have been very easy to care for. The goats have been incredibly hard to fence in the woodsy forage we want them to eat... My husband is definitely making plans for how we can just have sheep at this point, lol. Just our experience however. We are new and lacking in experience!
The sheep not only give us great milk, but their fleece isn't bad either. I'm not a connoisseur but I do like to knit and spin. The particular goats we have don't give us that option. Also, we are thinking of cross breeding the sheep to produce a hardier lamb that will be for meat production... not sure yet.
On a side note... both the sheep and the goats love our hostas (ornamental vegetation around here) and other ornamental plants. We've managed to keep them away from the Hazelnut trees though. We see the goats sampling bark, but not the sheep. Our sheep seem to prefer the broadleaf plants like plantain, dandelions and trilliums and will eat some leaves from low branches. To my husbands frustration (who would rather have lawnmowers that keep it looking nice, lol) they leave the tall skinny grasses intact.
Anyhow, I hope that is helpful. Congratulations on your new venture!