Kina Sona Tenu would be fine for you and your fiance. However, I wouldn’t have that playing for the tribute. It’s a song that a lot of people know, they know the words to it. So when your MILs pics will be up, they’ll be thinking of the words to the song and find it strange because the singer is admiring a really pretty girl he loves.
For your MIL… In Lamhon Ke Damaan Mein (instrumental) is a really good choice too along with Yeh Dooriyan that I suggested… not many people can figure out the words to these songs, so they just sound like really nice instrumentals. In Lamhon Ke Damaan Mein (the song/instrumental) could also work for the slideshow on you and your fiance.