HOW CAN I REMOVE MOLDED CEILING TILES ON CATHEDRAL CEILING ATTIC SIDE GRAVEL/TAR TILES WERE ORIG ROO

My house am renovating, has cathederal roof want to take back showing very nice wood beams.
Prior owner before my father inlaw, strapped all but 2 ceilings making them just 7 ft in height.
So while l am gutting the house, l am removing 2×4’s and the 2×2 strapping attached to the 2×4’s so beams are stained like livingroom and then sand paint off bedroom beams stain it.
Have to in bathroom raise to 8 ft due to chimney visable and hall same thing but can live with that .

The ceiling tile am hoping can get advise on the dinningroom, a bedroom mold very bad, a few other rooms along edge on lowest point in line with eves trop.
Other rooms show water stains from leaking prior to shingles being replaced 5-6 years ago no leaking now
inspected 2 times during heavey raining since removing false ceilings.
The ceiling tiles in the complete house were nailed on top of the wooden beams, at one time was the outside roof.

On the attic side of the ceiling tiles there is black tar and gravel the tiles are about 6-7 inches thick.
The 2 rooms that have allot of black mold, contractor said he will cut them out with a chain saw then put strapping on top of beams where the tiles are being removed to make more stabble.
To put new drywall on ceilings he said he will nail 1×2’s on side of beams and screw drywall to strapping the strapping he said will be at top of side of beams so as much of beams are showing as possible.

If the above works, still have problem of strips of molded tiles chain saw couldn’t remove and end walls on the 2 by framing on front back of house.
I called in a company who did my basement in 2002 removed molded 2×4 walls etc they said best to remove most of tile l can then there a place in town who sell a paint type liquid that will seal mold won’t spread.
If that works great, l am as well worried cutting into tiles that dust doesn’t make mold grow in other places or get on wood table etc.

Does anyone have any name of what l would paint the 3-4 coats of on tiles, wood etc before cutting with chain saw? Also have black looking mold on most off the blocks in the crawling space, does anyone know a product l can paint over the black on concrete blocks and something maybe same product l could paint on wood beams, floor joices pretty much paint everything in crawspace to seal in mold to not spread likely should put a 50-70 pint dehummidifier in crawling space going to install a HRV when done other work.
Please email me at [email protected] please with any advise contractor planning to cut with chainsaw wed thursday in 2-3 days if possible need advise before cutting starts.
Thanks so much in advance
James Reeves