No example with yi but still okay 
As I said earlier, I am not an expert on such stuff but it so seems to me that it either should be i with hypen or yi without hypen.
For example:
ulemâ-i islamiye or ulemâyi islamiye
I think y in the middle is this buffer letter and should be used after removing the hypen.
And I think ı and yı forms of the affix are from the vowel harmony.
In my book (Hayati Develioğlu - Osmanlı Türkçesi Kılavuzu 1) it says if a word ends with â or û you put -yı,-yi. And there is still a hypen. And about -yi there is no example in the book. So I think maybe sometimes it can be used instead of -yı.
