Forgive me if I missed it; Where are the German coaling stations in the Carribean, or leading to it?
It is indeed a logistical challenge. I'm sure the Spanish would be happy for Germany to coal in the Canaries as a jumping off point as a form of vengeance but I doubt it's sufficiently close.
Have you ever heard of a fleet collier?
Not sufficient. It's slow to coal a fleet at sea and you would require a lot of time. Also more Colliers are required than the Germans would have to support the fleet so far from home ports.
Perhaps the British would sell some older colliers at a premium price in order to ensure that the Germans make it to give battle with the Americans.
Britain hoping perhaps for a double knockout that would allow them to cut naval spending by even more than the Russia Japan war. 1904 would see wars involving the second third fourth and sixth most powerful navies in the world.