how to choose a dual power supply for rail to rail amplifier?
I like the cheapest solution US $2.88 

But provide room to add a tin-plated brass or steel foil Faraday shield with an RC filter to desireable breakpoint near 10 Hz. There may be noise from this to the source may need shielding, isolation and filtering. How much? depends on your specs.

Also, when the output hits the rail, there is no PSRR.  zero, 0dB nada, none

    Module 1 specs at bottom of your link says 20 mA minimum load for best results.

    3W DC-DC Boost Converter 3.3V-12V to ± 15V Output Step up Power Supply Module.   
　
 Description:◦  Features:             


         ±15V step-up module, 3W positive and negative output boost module, low 3.3VDC input, non-isolated DC-DC 
Power modules, Can replace LM78XX / 79XX three-terminal regulator chip.           Wide voltage input: 3.3-13VDC     Boost Dual output: ±15V     Efficiency: 82%     Size: 23.5 * 14 * 6.3mm 

Support single in-line or horizontal installation DIP 


Conversion efficiency: 5V input, full 3W output, 82%

        -  Ripple noise: **5V input, full 3W output, 60 ~ 120mV**.  
             - Port definition:                   VIN: 3.3V to 13V DC input     GND: Input Output Common GND     +Vo: Output Positive.         -Vo: Output negative.       NC: Vacant port, no electrical connection     En: Module enables:     VEN &lt; 0.8V, the module does not work;     1.4V &lt; VEN &lt; VIN or EN vacant when the module normal output.
   NOTE: VEN &lt; 0.8V, the circuit configuration restrictions, +Vo Vin voltage output at this time still, but -Vo no voltage output.


  
Precautions    


The module does not support output short circuit protection board.      
The output current is greater than 20mA can get a better product overall performance.    
When -Vo overloaded, + Vo load is too light, it is recommended to increase the dummy load resistor between ground terminal and + Vo terminal.