They told me I can come to the food bank once a month. If I came in on say, Jan 18th, can I come in Feb 7th?

yes

Yes. Doesn't matter what Friday in any month. Two Friday's in a row is fine as long as it's only once in any given month however you can go every Friday for any breads or produce displayed outside. The 5 Friday rule of months is the last Friday of the month is free only.

Yes. They way they explained it is you can come once a month, even if you come the end of one month and the beginning of the next. Months that have 5 fridays, you can come twice in that month.