You can use dry powder or foam for a diddy fire like that,if the blast
from the propellant is a problem you aren't using it right.Both work in
the same way as the fire blanket,suffocation with powder chucking a bit
of chemical in too, so you're not aiming at the base of the fire like
you would with a water or a co2.So if you're chucking fat everywhere
you're making a bit of a pigs ear of it.
Having said that,if it's big enough that you're not confident to tackle
it with a damp tea towel my advice would be to isolate the heat if
possible,shut your door and get out.
Forget the paint,your platerboard ceiling will give you enough
protection,but if you've got breaks in it ie downlighters then you
should get some of the hoods that mount above them in the void to
prevent invisible fire spread......'it's in the walls!'