Sunscreen (very expensive to buy there) and aloe vera (just in case)
I brought clothespins (I know that is not a toiletry but thought I'd mention. They were helpful for everything from closing the snack bags I brought, to securing the bathing suits while they dried on the "string" thing in the shower to securing a rain poncho to my childs stroller during a brief storm.
Instead of buying the travel sizes, ask friends if they have hotel shampoos sitting around, pretty much everyone does. I just empty out the hotel brand and fill it with my own stuff making sure I know which is shampoo and which is conditioner. Our local dentist gives freebie toothpaste in the small sizes. I use an old aspirin bottle for all our meds so they are all in the same place (but does involve some digging for exactly what you need).
Shout stain wipes
You probably already have antibacterial soap and wipes in your diaper bag.
I only brought my "necessary" makeup (vs my entire makeup bag) and my skin care products. A couple razors and trial size shaving cream that dh and I shared (we didn't share razors, just the shaving cream).
Don't bring a hair dryer, Im pretty sure all the hotels have them. I left most of my hair stuff at home since I didn't need gel or hairspray, I was pretty casual the whole time.
I packed each outfit in a gallon sized ziploc so we didn't overpack. I had one for each day. I could fit dh and mine in one and the kids in another so they just pulled it out and wore it with no hemming or hawing over what to wear. The bags came in handy to hold ice and bottled water that we brought into the park.
Just make sure you have plenty of diapers! Those are expensive too. And swim diapers! They WAY overcharge!
Have a great time!