2. Gift money must be paid. You can give it directly to your classmate (better not, because he has a lot of things to do that day and may lose it. Maybe later, he can't remember how much gift money you gave) or give it to the cashier (it's a special bookkeeping, so write down your name and gift money), which is relatively safer. As for the amount of gift money, do what you can. Students are generally not less than 200 yuan, but more than that.
3. Just send gifts and wine! There's nothing wrong with it.
Have a good time.