riviera maya is a stretch of coast that comes after cancun...i believe is from playa del carmen to tulum?
playa del carmen is one specific small area...very nice beaches.
as for photographers - this is dependent whether the resort allows outside vendors. some places say you can use any vendors you want (but they have a suggested list,) others say literally "if you want photographers/flowers/entertainement or whatever...you *must* use someone from our list or not have it." and some places will only allow you to bring in your own photographer if you pay an outside vendor fee...or a hotel room for them for one night. others, like the haciena tres rios for example will insist on their dj/lighting equipment...but you can use photographer of your choice
so it really really depends where you choose. and rules can change from year to year...a bride being allowed something last year is no guarentee you will be allowed it the next year
in packages...they are set and you cant reduce them BUT photographers are often listed as an extra and you can choose if you want one or not
i dont know if i explained that well or not...feel free to ask for clarification =P i used a non-hotel venue so i dont know much about resort specifics