Advice on generating a negative supply rail (-5V) in an embedded, mixed signal design
Your use of the inverting switcher is a reasonable idea. However I would suggest a couple of things to improve the analog front the performance. 


Have the main converter LMR23625 produce 6V instead.
Use an LDO to produce the 5V for your analog.
Have the TPS63700 invert the 6V to -6V instead.
Use a negative LDO to produce the -5V for your analog.


This will give you the quietest voltage rails for analog as long as you work to isolate the GND regions properly for analog as well.