First of many updates:

New Base casing and PCB

good: PCB fits like a glove in casing and casing fits like a glove to phone
bad: i2c contact pads are completely in the wrong place. minor mistake.

New Bottom casing and new PCB

Good: fits like a glove. the casing sort of goes around the pcb now to hold it in place (see next pic), that was a good decision cause loosing the screws on top looks good and will make construction a lot easier and faster.
Bad: no bad discovered yet.

Overhang of casing over PCB marked red, dotted green line is PCB under casing


Contact spring alignment is perfect


Bottom with keypad mockup in black, no screws