I'm getting ready to try some new cocktails, and I have a slew of questions...?

I think you might have trouble sourcing the rhum vieux here in the states. I may be wrong, but I haven't seen it except in duty-free airport shops.

Yes, the average liquor store will carry Bacardi 151-proof. Since you're doing a float, I'm going to venture that the body of the cocktail will not be that high-proof rum, correct? When your cocktail is made, hold a tablespoon at an angle almost parallel to the surface of the cocktail and slowly, slowly pour your high-test booze over the back of the spoon. You're basically using it as a diffuser.

Cure-a-sow is how I've heard it pronounced.

And vanilla beans or pods can be purchased domestically right in your friendly grocery in the spice aisle. They'll be in a glass jar, and you should go to a high-turnover market to purchase them; they have been known to go rancid. You can use the entire pod, or scrape out the seeds and use them, but it will necessitate using a chinois to strain your cocktails.

I can help you with the pronunciation:

http://www.thefreedictionary.com/Cura%C3%A7ao

Vanilla beans ( or vanilla pods) should be pretty easy to find in a supermarket, or grocery store.

I'll ask someone I know who is an expert on all things liquor and cocktails and get back to you if they have the answer to your second question.

Good luck!