Are these component values and functions proper for this device given its datasheet?
The optocoupler does not have a high-impedance input, and requires a current to flow to turn on, so you do not need to protect against a floating input.

The pull-up resistor, together with the parasitic capacitances of a few pF, forms an RC circuit. You would need 280 Ω to get 1 Mbit/s out of this chip, but if speed does not matter, increase the resistor to save power. As shown in the datasheet of a clone (PC900), you are not expected to use more than 10 kΩ:



The H11L1 datasheet does not mention a decoupling capacitor, and does not even have it in the test circuit. However, you are doing digital switching, so I'd rather add one.