What is the proper placement of the feet on the pedals when viewed from the top? When placing my feet on the pedals with the balls on it, the outer part doesn't fit the pedal anymore. If I moved the foot backwards, the pinky would not be on the pedal anymore.

I wonder if that is an issue or no problem at all.
The ultimate rule of bike fit, is that if it works for you (i.e., no pain or discomfort) then don't worry too about it too much. Once discomfort or pain becomes an issue then you will have to start to focus the cause.

In regards to generally accepted foot positions, right now most fitters are recommending having the axle of the pedal (the shaft that connects the pedal to the crank) between the 1st metatarsal (ball of foot) and the fifth metatarsal. 

This puts the foot forward about 1 cm relative to lining up the ball of the foot with the pedal axle. Given your description of the problem, moving your foot forward would bring more of your foot onto the pedal platform, which could address your issue. 

Is this even a problem?

If you are not currently experiencing problems (i.e., discomfort or pain), then arguably this is not an issue.  Not having your full foot supported could however cause discomfort on longer rides if you use soft shoes, as your foot will be bending around the pedal platform. This would be less of an issue with cycling specific footwear, which have stiff soles to better support the foot.