A: Yes, you can download it here. Instructions for setting up a UDC in N1MM can be found here. To ensure you have the latest version of the UDC file, it is suggested that you update it just prior to the commencement of the contest.
A: Yes, this is encouraged, especially if you are entering as a YOTA.
A: The simple answer to this question is you should ensure you have the correct information prior to the QSO being completed. You are encouraged to enter into a discussion with the operator, which can include double checking that all the information required for your log is correct.
A: It is completely up to you, but do ensure that the conversation is respectful and avoids any topics that are likely to lead to negativity. Some sample questions are: