Azeri Turkish vs Ottoman Turkish vs Modern Turkish?
Azerbaijan Turkish and Turkey Turkish are very similar. They are of the same root, but there are a few grammatical differences. An Azerbaijani Turk and a Turkish Turk can easily understand each other. For your second question: Ottoman Turkish and Turkey Turkish are the same. Ottoman Turkish had the same words but the alphabet was Persian Alphabet. Modern Turkish is the continuation of the Ottoman Turkish. So, you cannot ask a question like "which one is closer". Turkey Turkish and Ottoman Turkish are the same languages with different alphabets.