Unfortunately no, you can't use those campfires as traps (this limitation actually makes sense from a game balance perspective). What's interesting is that while campfires themselves aren't interactive trap points, the game gives you plenty of other creative ways to approach stealth situations. You can actually do some pretty clever things like leaving bodies where patrols will find them, which creates perfect ambush opportunities (timing is key here, as different guards have different patrol patterns).

The environment is really your friend here - smoke bombs and kunai are particularly effective since they work well with the shadow mechanics. Speaking of shadows, here's something neat: extinguishing light sources actually expands the dark areas you can hide in, which becomes crucial in later missions where guard density increases.

I should mention that while you can't rig the campfires, understanding how enemies interact with their surroundings is still important. Guards will investigate disturbances in a pretty predictable way, and knowing this helps you set up some really effective ambushes (try using bells to draw guards away from their posts - this works especially well when combined with shadow zones).

Keep in mind that these mechanics might get updated in future patches, but for now, focusing on the tools and environmental manipulation the game does give you is your best bet.