Wow, you're absolutely right about that. It appears to be a bug/"feature" of the flight simulator, as the input event "K:PITOT_HEAT_TOGGLE" is completely disabled when there is a pitot blockage. Given what I have seen under the hood of MSFS, I suspect that behavior has been there since at least the early 2000's. I've been contemplating creating my own elaborate simulation of pitot-static effects, which would solve that problem as a side-effect. Thanks for pointing it out.
What a tiny detail on the ADF instrument! I've fixed that now. It was very easy, as you said. Thank you!