Say there is a non-NATO, non-EU country, yet not Ukraine, at least not yet. (I stipulate the last because I don't want the current crisis to yet color the answers.)
What are the actual requirements as listed in the treaties or charters for defense and/or aide to be provided by other member nations, if:
The country is granted EU, but not NATO membership?
The country is granted NATO, but not EU membership?
Do things drastically, or at all, change if both are granted?