no worries! Yes it is fine to put it in radians but personally I would recommend degrees
Respectfully, I disagree. For methods, typically you're using sin, cos, and tan in the context of circular functions, not in terms of geometry problems - and when using them in functions, you're also usually using them in radian mode. Radian mode is honestly just better for methods and specialist, and you just convert to degrees (by adding the degree symbol - on the old CAS, it was ctrl+') if they ever do ask you in degrees.
You only put a neg in front of the integral when the area is with the function below the x-axis and the x-axis itself. Like you said, when it is between 2 functions, its just top-bottom function and you dont put a negative out the front, despite its location on the plane. LMK if this doesn't make sense
I also just want to add to this - the reason you don't need to split them up when there's two functions is because the negatives and positives end up fixing themselves. It's very long and complicated to show why, but it's not just a case of, "oh, this is an exception to the rule" - there's a reason we can do things differently in this case, and it's worth understanding that reason.