"The largest OCP device will be 30 amps with #10 wire."
How many current carrying conductors do you plan on having in this 2" conduit? Between just 10 and 20, you must derate to 50%, which would make the maximum ampacity of your #10 THHN 20 Amps. If you've got visions of running a whole panel's worth of wire through a 2" conduit longer than 24", forget about having #14, #12, or possibly even #10 as part of the equation.
"1 or 2 #10 grounds"
Just run 1 properly sized conductor, or simply mount the ground bar in the box, and run none at all.
