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.

By the way u and ü means "ve(and)" in Ottoman Turkish. 

Examples:

say u gayret

şan u şöhret

ilm ü marifet