The powder was everywhere. Yes, it will be turning up for weeks or months. There are some aqueous foam models and sprays that are more expensive but less mess, fwiw. As well as CO2 of course, ignoring the difference in intended uses. One of the "sprays" is called Tundra and apparently it is a fairly clean way to hit small fires.
You might consider using "fire jelly" instead of alcohol to preheat. You can buy it in tubes, like toothpaste, or make it up easily yourself. Take some white canning paraffin wax, or old candle stubs, dice it up, add some naphtha or similar petrosolvent, and let it sit in a jelly jar for a week or two. The wax dissolves and gives you a thicker white version of vaseline, except it is wax not grease so it burns cleanly. Add to a tube (from a pharmacy or camping store) and you can easily control the preheat by squeezing a small ribbon of fire jelly into the cup instead of the alcohol. the jelly can't run off, and burns with a visible flame.
The rule of thumb for the small powder exinguishers (about a liter size) is that they can put out "one trash basket" worth of fire, and they'll be gone in 30 seconds. The problem being that a fire will also usualy double in size in 30 seconds.
Glad you got it under control so quickly!