I don’t buy into 10R resistors despite their near ubiquitous use. If you’re using them as fuses, they’re not designed as fuses, they won’t work reliably as fuses, and if they do you have a mess to unsolder and replace before you can get it working. Whereas polyswitch fuses really are designed for the job and will reset once you’ve cycled the power.
As for keyed power headers, I use them, but they aren’t perfect. An incorrectly made cable has been known to defeat one. True, I have and use a cable tester. In fact I can’t recall ever having connected power backwards to a module, nor burned up anything (other than on a breadboard) with a short (I always test for shorts before first power up, and there are polyswitch fuses in my power supplies).
I use diodes, but more out of habit than anything, and because you have to put something in that footprint if it’s not your PCB, and if it is, someone else is going to want that footprint there.