anyone's church only have a piano and not an organ?

Yes, my FH is a musician and he has done it for many weddings and his friends who does a lot of weddings also are doing it for us- they usually charge about 700 but at least we get a discount. What also sounds really pretty is a trio with strings and a flute. We want classical music such as Canon in D.
Actually, I see that you are getting married at St. Pat's same as us and they actually have both an electrical piano and an organ from what I remember.