Not using the same email address, no. They would have to either have separate email addresses or be FB-linked to different FB accounts.
Pupils dont get money from you upgrading or exchanging current dorm mates to higher tiers, only if you put new ones in a empty room. You can continue to upgrade that way if you want to avoid giving them money. But even then the money gained from new dorm mates is super tiny
Send a help ticket and they will take the strike off your silence tiers. Otherwise your next silence will be 7 days