Question about proper PCB stack-up
I would go with this : 


Signal - Power
Ground 
Power distribution &amp; ground
Signal - power


Signal on top is obvious, it is to avoid vias as much as possible.

Ground on layer 2 is obvious too.

I usually use Layer 3 for power distribution, it helps a ton to keep the signal layer as clean as possible, and allows optimal routing of power traces. 

I try to avoid inner signal traces, it makes debugging &amp; rework much harder than needed, so layer 4 is for signal.