Interest bearing loans & Transactions

Q: I have a friend, who borrowed some money from me a while back. He sits in a grocery shop, owned by another friend who is out for three chilla. I often go there and even sit with him in the shop and talk. From the beginning of our friendship we often entertain each other (with food). However after giving him the loan I was feeling reluctant to accept his invitation. I even expressed my cause of reluctance to him, to which he replied that he did not have any such intention prior to inviting me. Hearing this I accepted his invitation, keeping in mind our friendship that existed even before giving him the loan.

Recently I heard a lecture where Maulana Sulaiman Moola narrated a story (which more or less means) that Imam Abu Hanifa (ra) did not even take the shade of the tree of a person to whom he had loaned some money, cause he did not wanted to get any benefit from a person to whom he gave a loan.

(After hearing this) The next time that friend of mine invited me; I politely refused to accept it citing my reason. Now please enlighten me on what to do. Should I make a rough calculation of the amount that he might have spent to entertain me, and then when I take back the money should I take that amount less and what about my friends remark about his intention. Please let me know what can I do?

Q: Zaid is willing to lend a Islamic School 50 thousand pounds for a year, on the condition that at the end of the year he gets his full money back, on top of that the School will have to pay him 400 pounds every month,so in total at the end of the year the School will be paying him 54 thousand and 800 pounds,(4 thousand 800 pounds extra) according to Shariah is this permissible,If not permissible could you please explain a Sharee method where the School may borrow money of Zaid and he may also benefit?

Q: Is it permissible to apply for a bursary at a bank? E.g. Old Mutual.