What are the main differences in Giant's Toughroad and Revolt drop-bar bike series?
I think you are confused about the frame 'technologies' that Giant offers. More boxes checked does not mean a better frame, the choices are mutually exclusive. 'Advanced Composite' means a carbon fiber composite (CFC) frame. 'ALUXX' means an aluminium alloy frame. CFC frames are generally held to be superior to alloy ones.

I'll give you that the 'SL' and SLR postfixes are confusing, intuitively they would appears to indicate a progressively higher grade of either CFC or alloy construction, but the lowest spec bike has the SLR tag. 

It's very obvious that the Revolt Advanced is the better bike, and the Toughroad the inferior. Generally the Toughroad series sits below the Revolt in Giant's range, with a bit of overlap.

The 'gravel', and 'adventure' adjectives don't mean much. Asking who are these bikes are for is a kind of meaningless question. What you should do is find stores that have the bikes you are interested in, sit on the bikes and do some test rides. Figure out which gives you the riding position, ride and handling you are looking for, then decide how much money you want to spend and which level in the range you want to get.