IMPORTANT!!!! music at my dad's wedding reception...?

If you have no music or melody for the lyrics, then you have no song really. You can't hire a guitarist to play a song you haven't finished writing if the music doesn't exist. Karoake isn't going to help you either because you can't sing your lyrics along to some random music, you have to write a melody for the words and then musicians can figure out what chords to play. I think you dragged your feet too long, it's too late to perform the lyrics as a song at this late stage. You should either read the lyrics as a poem as part of your toast (IF you were asked to make one), or print them on nice paper and frame the song and give it as his wedding gift.