Hi, Sleeper
The short andwer is yes, and yes and in that order
You can put them as close as you like - there is a range of ESCs which are soldered directly to the terminals of Speed motors
And Yes, the motor will produce interference (related to the load current, voltage, spped and condition of the brushes) which does not matter to the ESC
But it may matter to the receiver, so this is why the motor should be fitted with supression capacitors (usually 3 of them)
hope this helps
andrew
