@KSchaum I don't know anything about dreams resort ( I am getting married at NOW Sapphire in June) BUT there is a ton of information on this forum regarding shipping vs. bringing your decorations down. You can search in the box above for different posts but after reading dozens of posts about this the consensus from the brides was DO NOT SHIP ANYTHING DOWN. Mexican customs is shady to say the least and most times your package will never make it to the hotel.
Most of the girls just had different family members check an extra bag with the items in it. Additinoally each bag can't contain more than $300 worth of purchased "new goods" and you'll have to have your receipts handy incase you get your bags checked at the airport. If you tell them its for your wedding they usually let you through but just be prepared( that was the feedback from some of the postings)
I'm going to just bring a few big duffle bags and check them for my welcome bags contents. I'm trying to keep things to a minimum that I haev to bring down ( No glass) I am renting glass vases from the florist to eliminate having to schlep those down. Chair sashes, table runners,etc. don't take up much room and the welcome bag contents I am packing and then assembling the bags down there ( I think that's the only way) I've been keeping all my receipts and I"ll divy everything out in different suitcases when we head down. I hope this helps.
The bad news is it sounds like a process
The good news is not one single bride had any issues with their goods at the airport as long as they had their receipts and all their items made it just fine in the checked suitcases.
Let me know if this was helpful and if you need anything else.