Simple stereo audio mixer power supply
Other than missing decoupling capacitors, there is nothing obviously wrong with the schematic as shown.  There are no values for R8 and R11, so the intermediate stage gain is unknown.  If it is more than 10-ish, offset error voltages from the preceding stages will show up as a non-zero DC voltage offset on the output signals on opamp output pins 7 and 7, reducing operating headroom asymmetrically.  But with +/- 12V supplies and low gain this should not be an issue; just something to be aware of in a future project design with more gain.

The current in/out of the 2426 is the algebraic difference of all amplifier output signal currents.  Since all of the stages are inverting and there are an even number of them, many of these currents will cancel out.  Pay very careful attention to the 2426 datasheet for guidance on decoupling and output capacitance.  If the datasheet does not disallow it, add a large cap (1000 uF or larger with a 0.1 uF ceramic in parallel) across the 24 Vdc input.

For ease in future discussions, add reference designators to the opamps and connectors.