Back when I got married, you paid for everyone whether they drank or not. They did end up giving me a slight deal on the two kids that were under 2, but they had said they wouldn't.
The tulum poolside reception is beautiful and I don't think you NEED a light up dance floor. It's pretty cool... but if you're looking to save money, most people don't get it.
There is a dress code for Arlequin. Long pants for the men. There are very few restaurants where this is enforced anymore, but that's definitely one of them.
I have photographed a wedding where they brought in hair and makeup. It was amazing and very relaxing to have the bride getting ready in the comfort of her own room. However, I have heard they are getting more strict on bringing in outside local vendors.