Ashley this is some info in Punta Cana area. The Bavaro Beach is where a lot of resorts are located the beach is a white sand beach with crystal blue water, very beautiful beaches. You have to look at each resorts to see if it's swimmable because i do know that some resorts have calmer waters. it has something to do with how close they are to the gulf i think, something like that. Mine is supposed to be swimmable. Most of the resort i looked into (Paradisus Palma Real, Iberostar, Paradisus Punta Cana, Dreams, and Melia Tropical Caribe) all had places for private receptions and gazebos. Dreams PC had a very pretty terrace with a beautiful view, i was going to book there but the WC was really hard to get a hold of so i backed out but that's when they were just transitioning from Sunscape to Dreams. But i do think i saw a post recently about some girls having a hard time getting hold of the WC there, you should look at that post and maybe pm a few of the girls to see if the problems were resolved.
I didn't do a site visit so i'm only going by pics for locations and talking to other brides on here, tripadvisor, and Debbie's dominican travels. My parents did stay at the Melia about 4 yrs ago and loved it there. Said the food was good, the beach was one of the nicest if not the nicest they have been to (they do travel a lot), and the resort was beautiful.
It sounds like some the girls dont' think cabo meets some of your requirements. I know that Riviera Maya, MX is a really pretty area too. I went to a wedding at the Aventura Spa Palace (adults only) it was very nice, there was a beach that had a lagoon instead of an ocean but it was really pretty. the lagoon was made so people could swim in the ocean otherwise it may be too rough. I have pics from our trip as well as from the wedding there if you want to see. I stayed at the Bahia Principe there too and they had large rocks placed in the ocean so people could swim in it too. I know theres a Dreams (Dreams Tulum) in that area i'm sure some girls on here could give you info on there and I think Moon Palace is nearby too, there were quite a few girls that got married there recently.
If you can do a site visit for the area you narrow it down too than i would. I think it would really help put your mind at ease. If i could of done one, i definately would of.
I'm sorry this is so long, i'm just trying to help. Please don't make yourself sick with worry, you can definately find a place you are comfortable with that your guests will love.