Well, looking into "variant.cpp" can help (I did it some time ago for the MKR WiFi 1010) but it is more easy to look in the documentation 
Another problem (or feature...) are the pullup resistors at A4 and A5 (4.7 kOhm). So A4 and A5 are not really analog inputs but they may work fine with thermistors (for temperature measurement): no external resistor needed 