Do these bolt straight into the factory fog light holes?

Yes — these mount at factory locations. No drilling needed. Test-fit before final fastening to confirm alignment.

Can I use these without a switch, or do I need to add one?

These come with no switch, so you'll wire them to your existing vehicle harness if it has one, or source an aftermarket switch separately. Check your vehicle's wiring diagram first.

What bulbs do I need to buy?

Standard H10 bulbs. They're not included, so grab a pair before install. H10 is a common bulb type, widely available at any auto parts store.