In order to be a valid deduction, you need the written statement before you file your tax return.
No, you need the written statement. That $75 exception for churches is about something else.
The excess amounts can be carried over to next year. So if there may be a chance you can use them next year, enter them all.
Form 8282 is only for noncash donations. That form does not apply to cash donations (which includes payments by checks or credit card).
