The way to determine if a flight is for hire or reward is to ask the question, if the flight did not take place, will the payment still be made?
In the cases of expenses, if you drive to the airfield and you get rained off, you have still incurred the expense of going there so it has nothing to do with the flight. Similarly if a club pays your seminar or instructor renewal costs it does not relate to any specific flight.
There are flying clubs where instructors are not paid for instruction and receive travel expenses etc or a daily allowance for being at the club. Provided such expenses are paid regardless of flying, they cannot be regarded as remuneration for the flight.