well, your dream wedding sounds LOVELY!
When you say formal wedding, do you want it in a church? Or just in a Gazebo type setting?
This photographer is very well known in the Riviera Maya. They do beautiful work... but more importantly they have posted a lot of their work on this forum to help people out! Check out this thread...
http://bestdestinationwedding.com/forum/t4276
That will list a LOT of the places where you can get married near Playa and also give you a visual of what the weddings are like.
This thread is about a wedding at the church in Playa and then a resort reception...
http://bestdestinationwedding.com/forum/t18777
Okay... now the biggest help is that these wonderful photographers also just got married in Playa!
here is their review http://bestdestinationwedding.com/forum/t15288
The most important part is that they had a band which they thought was AMAZING. Here is what they wrote
"Music: This was on Top of my list, I needed good music, and I found Balance, they are 8 musicians, play anykind of music, English & Spanish, they kept everybody dancing for 4 hours! Even in the breaks, the DJ selections were great.. I highly recommend them: Balance la Banda - Downloads"
I hope this helps!