Does anyone know if the AD Army is in need for fire fighters MOS 12M?

Someone in recruiting/retention would likely be who you'd need to talk to. I don't know what strength the MOS is kept at Army-wide, but I don't know that there are a terribly large number of Soldiers in that field.

Just my guess, though.

Unfortunately this mos isn’t ever really in need. It’s always whenever the army decides they want to “upsize.” Just speak with a recruiter and see what they say. Just be ready to have the 50/50 shot of either counting bullets or sitting in the fire house bored out of your mind.

Not likely, most are NG or AR, few are active duty.