For sure! The design doesn't have anything pressing hard up against the bridge of your nose.
Generally speaking, large is or most adults and small is for most children. With the adjustable straps, you are able to make a snug fit. Check out the sizing diagram on the product page.
Works just like a regular snorkel just with much better viability and comfort.
Won't be an issue at all. I fit it easily into my carry-on luggage with all the usual necessities. While it is bigger than your typical snorkel, it doesn't take up much more space and is totally worth it.
Yes, lift your head and blow the water out
Does the snorkel filter out water? While you are fully submerged? The snorkel tube will block the water from coming in through the top when fully submerged