OK, I had another go at this today, and in fact you can access the fog light bulbs from inside the engine compartment, but it's a tight squeeze. It helps if you have skinny arms.
The passenger side is the more readily accessible one, but I did have to temporarily disconnect the headlight wiring harness to provide extra space for my arm. Just stick your right arm down behind the headlight cluster, then reach forward.
Accessing the driver's side fog light required opening the air filter housing and lifting the front portion out of the way. I also disconnected the headlight wiring harness, but this side seemed a bit roomier for my left arm.
You'll have to remove and insert the bulbs by feel alone, as you can't see them at all from above. This is tricky, but not impossible. Just keep track of the fully seated and open positions before removing the old bulb, then reverse the operation on reinstalling the new bulb. I wore rubber gloves to keep from touching the bulbs with my fingers, and to fully protect the bulbs as I manoeuvred them up to the openings. Be sure not to scrape the sides of your bulbs when inserting them into the openings, or you may scratch off the coating (if any) on your bulb.