T5x models - differences T58A (rev), T56A, T57W?

[DS25]

Hello,
I'm a little bit overwhelmed by the number of different models available in the T5-series.

1) What's the difference between T58A and its hardware revision 2? Some retailers offer both.

2) What's the main difference (regarding features) between T56A and T57W?
- The T56A seems like a stripped-down version of the T58A, without video (also no incoming SIP-video calls?) and door phone features.
- The T57W seems very similar. Lower screen resolution, and seemingly Linux-based instead of Android.

Thank you.