And is it a problem if any of the cables are touching the mobo?
Very unlikely, but still try to move them around/stick them to anotherpart of your case.
If you fan is connected to your PSU, it will work at 100% performance 100% of the time.
If it's connected to your motherboard then the fans will only increase performance when heat builds up in your system.
I have my intake/exhaust fans connected to my PSU, and my CPU to the motherboard.