Routing a buck/boost DC/DC converter
I hope I don't contradict anything said on the previous question's answer!!!

The feedback point should be taken from as close to the output pin as possible. Note the track on the non-component side of the LTC3536 document. 

I'd use a full ground plane on the underneath all round but the low voltage end of R7 needs to get to pin 2 and then pin2 needs to star point under the chip to local full ground plane. 

I wouldn't tee off R27 (and pin 3) to feed the top copper that connects to the bottom copper (GND Plane) - I'd let (what you've called) GND plane flood thru to power ground where R11 is and as far up as nearly the analogue ground plane.

The track from pin 10 should attempt to keep to the top layer as much as possible so as not to interrupt ground planes underneath.