I love cruise critic but the site is having serious problems with lag time and timing out - takes forever to turn a page or post. For whatever reason (probably because the DIS is far better for
DCL) the Disney board isn't very active. I add some smileys over there by manually typing in the code like for wink I use semi-colon plus close parenthesis. There's probably an easier way but in almost 5 years, I've yet to figure it out
For the currency exchange - we aren't. We have to pay for our Sotos cruise in Grand Caymen in US dollars. I think our helicopter was billed to our credit card in advance, but I'll have to check that. The only thing we'll pay for is lunch and we can put that on a credit card to simplify matters. But from what I've found researching it US$ is widely accepted. Anyway i don't plan to shop there since they pretty much import everything but tortuga rum cakes (which my aunt has delivered to her every month and I just eat hers

) so things cost more. Currency rates fluctuate but the Caymen Island Dollar is sort of tied to the US$. 1 USD = about 80 cents KYD or 1 Caymen Island Dollar = about 1.20 - 1.25 USD. Their money is worth more than ours.
For Cozumel, US cash is king.
Like Lisa said, there won't be any major language barriers. In GC the official language is English. In Cozumel, most of the cabbies speak better English than some NYC cabbies. Unless you go shopping off the beaten path there shouldn't be any problems. If you are going to PB,the owner is from Canada I think.
My niece's b-day is 4/7 - is that Amber's b-day too?