Online shopping whilst living in a host fam?

Hello! I'm going on a 3 month high school exchange in a few weeks and im staying with a family in the Kobe area. I really enjoy lolita fashion and i'm wondering if it would be alright to online shop and have things sent to their home whilst i'm staying there?

Any other tips for a high school exchange?
Any good souvenirs to bring from Australia?

You'll have to check with your host family, but I don't see any problem as long as they are alright with it and it doesn't cause much inconvenience.

For souvenirs, I would bring some snacks that can travel well for the whole family to enjoy, then maybe something more personal for each person in your host family (for your host mother maybe something nice for the bath, for any kids some popular or traditional toys, etc.) Coins sometimes go over well, or stamps or postcards. I'd bring some extra stuff as well in case you meet some people you'd like to give gifts to.

In some cases, the local post office will be confused to see an unknown name at that address (and typically they will call to confirm the situation), so if you want to avoid delays, just put one of the family members' name instead of yours (of course, ask for permission beforehand).