A quick scan looks OK.

However, what's with all the diodes?
On the input side, I could see sense in having LEDs for diagnostic purposes, but on the output/LPT side, they don't really serve much purpose.
Also, will the 5V on the LPT supply enough current for all the optos?

If you're worried about protecting the 5V, I'd think a 5.1V zener would provide more protection than a diode on every opto.