For the led fire effect, the cheaper route to take is definitely this $12 set of pico chip leds tied to a 3 way fire circuit. 1 red Flickr and 2 yellow blinks at different speeds. It has a built in resistor,A model rectifying device also makes it work for ac/dc/dcc “digital command and control for digital model train stuff” and, I believe at either polarity. Pretty easy to hook up. Works at 5-19 volts, what a range, so, with this small set, the scale campfire could be emulated well enough and powered by a 9 volt battery, if you wanted.
I’ll try to shoot some test footage of this and the other two fire emulation circuits that I bought so you can see how they run and how they would need to be powered.