Merhaba!!

I have gotten to the point where I think I can say that I feel rather comfortable with vowel harmony of Türkçe, but when it comes to adding endings onto some American/English names,especially those ending in "y", like "Mary", I am not really sure.

If I were going to write "Mary's music" in Turkish, would this be correct?:

Mary'in müziki

Here I am guessing that "y" just takes the place of a Turkish "i".

Çok teşekkürler!

I think it should be Mary'nin as the last letter in Mary acts like a vowel.

Also the final k in müsik becomes a ğ

So Mary'nin müsiği.

right, because you have to think Mary like "Meri" in turkish.

Müzik should be with a Z though, not an S