kapusta, about the metrocard issue, in our school we were told that metrocards cannot be used on vacation. Say, on chol hamoed you decide to go somewhere via the MTA, even though the student card would work, it should not be used since the card is given to you so you can get to school and back. It would be considered stealing to use it for your own benefit. It would therefore seem wrong to me to lend it to your friend since technically the city does not allow it. And just btw, I believe you are given 3 rides a day (excluding transfers, obviously) on the card. At least that was the way it went in my days.
Hope this helped. Oh. And good luck handling your neighbor.