for the points
1. it is surely safer than the tube tyres.
2. fuel economy will not be impacted much if you do not change the size of the wheel
3. i think driving performance will improve as you will get a better road grip.

1. yes it is safer.. the chances of a tyre burst in case of tubeless tyres are very less, even when the tyre gets punctured u can drive on it for atleast 3-4 kms withouth the fear of the tyres tearing apart

2. No

3. No