We are installing an oversize double shower 5x6 ft with 2 separate shower, body sprays, both systems will be feed by separate 1/2 inch feeds from the 3/4 inch main. Will a 2 inch drain be sufficient or will the drain size need to be 3 inch? The drain is about 2 feet from the main 4 inch waste line.

Your 2" drain and trap should be able to keep up with no issues at all.