• Disney-themed wedding cake: yes (Cinderella and Prince Charming)
• Ben Folds' "The Luckiest" for First Dance:  yes, which makes up for the cake
• Substitute keyboard player:  yes.  Get well soon, DC.

"Mustang Sally" is another of those inexplicably-popular songs that wedding bands frequently take requests for (notice I didn't say we HONOR the requests because, well, come on - people sometimes still request "YMCA".  As an aside, I'm always amused to see politicians that oppose gay rights hootin' it up to the Village People.  Have they really never wondered why it's "fun to stay" at the YMCA?)  "Mustang Sally" was once a staple of the band's set list, and one of C's opportunities to "GET OUT THERE" and "SELL IT" and be "IN THE HOUSE" and lots of other annoying rap clichés circa 1989.
As performed by C it's a scripted bit of course, and starts after the solo section (let's pretend the bride's name is Imelda):

    "Now not everybody knows this, but Imelda and I have a history.  That's right, she and I were a couple!  I thought she was the greatest thing ever.  I bought her flowers; I bought her candy; I even bought her a car!  Yesss.  But then along comes Ferdinand, and she left me in the dust.  And all I could think to do was to sing,
    "Ride, Imelda, Ride.  C'mon, everybody!  Ride, Imelda Ride!"

As if this wasn't already enough, he proceeds to substitute the bride's name for an entire chorus, imploring the crowd to sing it along with him.  I'm going to type it all out so you can hear it in your head and thus understand why I wear earplugs to every gig:

    "All you want to do is ride around, Imelda.  Ride, Imelda, Ride!  C'mon, sing it with us!
    "All you want to do is ride around, Imelda.  Ride, Imelda, Ride!  C'mon, even you guys in the cheap seats!
    "All you want to do is ride around, Imelda.  Ride, Imelda, Ride!  One more time everybody!
    "All you want to do is ride around, Imelda.  Ride, Imelda, Ride!
    "One of these early mornings, I'm gonna be wiping those weepin' eyes, yeah"
    "Those weepin' eyes, those weepin' eyes, Mustang Imelda!
    "Those weepin' eyes, those weepin' eyes, Mustang I...  OK, I'm sorry.  I'll stop.

I've got a headache just looking at this.  Forget that it's dopey; it's syllabically offensive.

We recently did a member's function at a country club and there was an elderly woman in attendance (let's say, named Indira) in a wheelchair.  They asked us to dedicate a song to her, and somehow we ended up doing "Mustang".  Right at the end of the sax solo I leaned over to H and said, "he's not going to "Ride, Indira, Ride" a woman in a wheelchair, is he?"  She started laughing just as he began, "now not everybody knows this..."
The sax player pointed out at the end of the night that the other song we dedicated to the woman-in-the-wheelchair was "Walking On Sunshine."