If a landlord changes rent due date,does lease need to be redone to enforce late fees?

[xylene]

A judge is not going to see the landlord's VERY VERY large concession of allowing 2 payments as anything but a big favor that you took advantage of. You owe the late fees.

The other issues you mention, are irrellevant at this point.

Your time would be better spend on learning some money management skills and on increasing your income than a losing case over at most a couple hundred dollars.