Hi,
I just went with a group of about 8 friends on July 1-4.
We were looking for the beach front spots as well, just an FYI I don't think you will find many Beach Front type places. The layout of the place is the beach, then a row of trees/beach chairs, a path that goes along the beach and all of the accommodation is on the other side of the path. While you will not be literally on the beach, you can be on the beach in 1-2 minutes.
Accommodation - you didn't list a price range, but seeing how Villa Camilla is listed and I looked at that place as well.. I'm assuming you want something fairly cheap. To be honest, don't bother yourself with checking websites and being stressed out. If you arrive late a night, then by all means sort something out for the first night. But I suggest just walking along the path and checking out several different places.
Since we had a lot of people staying with us, we were able to negotiate the price down a little, I also got 2 free buckets of beer from our hotel bar... So don't be shy, they are more than willing to make a deal.
I wish I could remember the name of the place I stayed, but I was too preoccupied with living a short weekend in heaven!!! The place we stayed was about 25 USD per night, so divided by two, that shouldn't be too bad. We were in Station 2 and there were plenty of other places in that same price range.
Be warned - there is a group of 3 very adorable local girls (maybe 8-10 years old) who sell necklaces at night... I suggest you but some pesos aside to buy a necklace!
Enjoy your trip and feel free to message me if you need any more info!