They represent 4.5% of oil production it seems. It will be interesting to see what this means longterm.

"Oil" is not a homogeneous thing. There are different grades of oil and refineries are built to process specific grades of oil. UAE produces the so-called "Dubai Crude" oil grade, which is very sought after.

Probably not much unless others follow suite.

It could be the first domino. They do have a port on the Gulf of Oman fed by a pipeline from their major fields well inland. This may turn out to be minimal for the world, but it could be huge for the UAE and their major customers.

4.5% most likely capped to meet OPEC agreements. There's no ceiling now (although, it will obviously not be 100% or even close).