When you meet with an instrumentalist they'll potentially be pleased to play many different pieces for you that may be used for the processionals and the recessional. How many songs? Its everyday at marriages to incorporate a single vocalist singing anywhere up to 4 selections in the rite - depending on the length.
This is mostly accompanied by a piano, harp or guitar. He generally toasts the bride and bridegroom, and also acts as the Master of Rites for the evening. Ultimately the daddy of the Bride will give his speech and thank everybody for attending.
Spontaneity is the way to go and masses of folks get up to toast the bride-to-be and groom. Of course, there's such a thing as too many marriage speeches. The times when wedding etiquette was etched in stone are long past.