I've reached a bit of a cross-road with competing goals. In starting to lay out the schematic, I've started to run short of GPIO pins on my nodemcu. I'm not completely out, but I'm running low. (I had originally planned to use a Wemos D1 mini because I had some on hand, but that ran short of pins right away.) I guess I knew this was coming since I can count, after all, but now I've got to deal with it.

I think my choices are:

1. Reduce the scope of some of my desires. For example, stick with only 1 remote switch instead of allowing for 2.
2. Switch to another microprocessor board with more available GPIO pins.
3. Find some off-chip way of expanding the number of pins, either using the otherwise-unused SPI pins or some other helper chips.
4. Combine some of the signals with simple boolean gates. For example, I'll have 2 PIR sensors, but I don't care which one (or both) triggers.
5. Put controllers in the remote sensors and/or switches and design some simple protocol for those independent brains to talk to each other.

I'm going to go with choice 1 for a couple of reasons. First, this is partly a learning exercise, and maybe I'm already learning enough :-). Second, complexity kills, and this is already pretty complicated. Third, I expect the software to handle the sensor inputs (which is the majority of the pins) with interrupts, and that's simpler if they don't go through some helper chip. I'm skipping item 4, at least for now, because I have some hazy ideas for treating things distinctly, which I won't fully figure out until software time.