The 4200 will handle all of that. Any modern processor will handle that anyway. So onboard will be perfectly fine.
I guess my suggestion would be to try to go low power. This would mean going with an Intel Core i3 or Pentium G####. Also get an 80 Plus power supply. Bronze or Silver rated would be good, but you'll pay more for them. The onboard video should be fine, but in the off chance it isn't then you can always add a dedicated video card, and power consumption, heat, and noise should still be low.