The SMPS should be enough of a reason to place the linear regulators in the digital section. However one needs to look very closely at the specific design requirements. If these linear regulators are meant only for powering the analogue circuits then maybe they should be in the analogue area. But in that case I would certainly not put the SMPS connector in that area. Instead I would put the connector in the digital section and place the linear regulators very close to the plane join area. However this is not as simple as that because you have to be careful to consider all current flows through the GND return and the impact that may have to the analogue circuitry. The picture that was drawn before was made with the understanding that the AVDD would be the same voltage level as the DVDD used by the MCU.

You should look closely at the proposal to use +/-15V for the analogue circuitry. These days almost all analogue signal conditioning for an MCU can easily be done using a 5V supply. You can greatly simplify your isolation and GND plane treatments by not introducing additional voltage rails.

Michael Karas