12/3 w/ ground run from switch to ceiling fan. Way to jump 12/2 for new light with independent switch?
Yes, providing there is enough capacity in the j-box, you can just run 12/2 w ground to the new light location from the fan j box, attaching black to red and white to other whites.

12 awg requires 2.25 cu in per insulated conductor, plus adding one conductor to the count for all grounds. The fixture wires from the fan don't count.