are u mean SEL55F18Z & SAL50F14Z? if yes, here's my knowledge

1st, SEL55F18Z is E-mount lens, which used with E-mount camera, and not compatible with A-mount. SAL50F18Z is A-mount lens, which used with A-mount camera. with certain lens adapter, u can mount A-mount lenses with E-mount camera, however u need to know the adapter compatibility before purchase

2nd, F1.4 DOF is slightly shallower than F1.8 DOF, although it may not so easy to notice. however, F1.4 has 1/3 stop faster than F1.8, thus it's has a slight edge in low-light photography. but again, if u using E-mount camera, u need an adapter for attach the A-mount lenses to E-mount camera

both Zeiss lenses optical quality is quite good

my personal opinion, SEL55F18Z is very good enough

hope this info will help u

APS-C lenses 32mm angle of view is 48mm equivalent with full frame camera

Other than canon aps-c sensor, you times the lens focal length by a factor of 1.5
32mm x 1.5 = 48mm

given that 50mm f1.8 on full frame and the 32mm f1.2 on aps-c and both shoot wide open, more or less you will get the same bokeh iinm..

this video might help you understand better..