I had a chimney fire 3 months ago in Penna. They had the hoses on the house for about 2 hrs. The attic was charred right across from heat so they had the hoses on the underside of attic of most of house. It was drizzling through much of the house a week later. There was a lot of soaking right to basement. Of course we are not living there.

Restoration tore rugs out right away. But there has been no heat or dehumidifiers put in, not exactly sure why. Electricity was off for about a 2 mos but they have service now.

So now I have fight with insurance company on what needs to be replaced. They are replacing my hardwood floor but not its' subfloor, It had some but not alot of water on it. The whole house was super humid for a month and the temperature has been fluctuating from -10F during long cold snap to 50F for a couple day. The windows all fog up on rainy/misty days.

I'm only learning about all this now, since I got their estimate and made a visit with MY contractor. They are replacing subfloor in main damaged fireplace room. But upstairs hallway and bedroom got real wet too.
I took some pin moisture readings today of subfloor.
Master bedroom - 16%
Upstairs hallway - 15%
other bedrooms - (little fire water) 11, 11 & 12%
so the master bedroom and upstairs hallway (heavy water!) have high subfloor readings 3 mo.'s after fire. My contractor says they are Done. Other bedrooms might be ok.
It's a total mess! Big huge house, lots of money involved. Their contractor told me they would dry house out right away and they never did. I am thinking the whole thing needs to be torn down or I am always going to have problems.

Your house has probably dried out a lot, without heat or humidifier. You will need to dry a little more before the re-building starts. Rebuilding the house is not necessary. Wood can get wet and dry out without loss of strength. It may be that you will need extra fasteners to secure loose boards. This is not much different than starting with new construction, after the roof gets repaired, if it is leaking. I think charred wood needs to be sealed to keep the smokey smell from permeating the house.
New solid sheathing for sub-floor was delivered around 19% when I was laying planking in the 70's in Oregon.
Warm the house up for two weeks at least, like you were living there, before doing any finish work.