Hi

I am initially designing a small PCB module (2cm x 4 cm), which will be a power module with VIN, VOUT, ENB and GND.

Instead of using PCB Edge plating, is it possible to place PADS on the base of the PCB like a QFN component? Maybe have a pad on each corner of the PCB

 

Probably. Depends on how you plan to do the soldering.

 

I would put thru-hole pads on both boards and solder pins to the boards.

 

Probably. Depends on how you plan to do the soldering.

These will be placed using a pick and place, and reflow oven

 

I would put thru-hole pads on both boards and solder pins to the boards.

I am trying to avoid hand soldering or connectors.

 

These will be placed using a pick and place, and reflow oven

You might want to get in touch with an assembly house and see what they have to say/suggest. This kind of stuff is, after all, what they are in business for and what they are experts at.