Difference between tsc in L0 and L1

Hi, I'm about to start a touch keyboard aroun STM32L052 or STML151, but I'm not sure which one is easier to use.

I'm using STM32CubeMX for project inicializacion.

1) The keyboard will have 13 keys, and I'll use an STM32L052C8, which lets me use a group as shield input an 15 keys, or an STM32L151C6, with 13 keys but not groups left to use them as shield. So, for this last chip, I can use multiplexing technice, as stated in AN3236 and get a free group to use it as shield. 

2) My app will support a wide variation in temperature (from -10 to 45°C), so,  its necesary to use NPO caps? Or can I compensate temperature difference sensing a cap with a similar temp coef connected as a key in a channel dedicated to that? (I know it can be crasy idea)