For the fog, I'd recommend checking this tips and tricks video and try using 'Lights' to create your fog over your jacuzzi. I used the omnidirectional light as the video suggests, most of them have the 'Haze' option, so you could try them out to see what is best for your project.
https://youtu.be/VtrS24gTViU
The 'small fire' can be reduced or enlarged. After selecting the object, go to 'Transform' and change the scale values.
On the pictures attached:
Right small fire = Original size
Middle small fire = X:20, Y:20, Z:20
Left small fire = X:300, Y:300, Z:300
Removing smoke is not possible since it is an animated object, I would recommend working with very low lighting around the fire, this will reduce the visible smoke as you can see in the night picture.