Dual supply PCB layer stackup
I would suggest something more like this:


Signal
GND
+3.3V/+5V/-5V plane shapes
Signal


There's no reason why you can't have your power supply layer have a bunch of smaller plane shapes where they're needed.

As with any four-layer PCB, you'll need to follow some high speed guidelines if you have signals with content >100MHz or so (many square waves even at low frequencies contain frequency content this high). This is especially important for signals on layer 4 since you'll have plane breaks on Layer 3:


http://www.ti.com/lit/an/scaa082a/scaa082a.pdf (especially the parts about return paths and loop areas)
https://www.intel.com/content/dam/www/programmable/us/en/pdfs/literature/an/an315.pdf (the part about "Discontinuities related to a transmission path")