How hard would it be to install 2 more off-road lights to my bull guard and put them on the same circuit as the headlights? So when I pull my headlight switch the 2 extra lights will also turn on?

 

I wouldn't put any lighting on the headlight circuits directly.

What I would do is put relays on the headlight circuits, which draw very little, and use the contacts of the relay to connect the new lights to the battery through an appropriately sized fuse.

This way, if the lights get broken, short, or the wiring goes bad, your headlight fuse won't pop and leave you with no lights at all.

Also, direct wiring to the battery also gives you more current than going through the thin harness wires that you'd be overloading.

Hot wires resist current more, then get hotter, and resist current more, and this continues until the overloaded wire burns up. Assuming the fuse doesn't pop first, which of course you'd prefer.