I did upload a new software version to the bitbucket repository. Now the input latch is supported. And I fixed also the wrong order of the input Pins, which I did noticed when comparing it directly to an original TIL311.
The latch pin is slower than at the original TIL311. This can be already noticed when controlling this pin manual by plug/unplug the wire on a breadboard. One thing I will try to fix that is a external interrupt triggered by a negative edge on the latch pin (RA3 on the PIC).