congratulations on finding a used Hitzer hopper stove,, they rarely are found used..
Fot the brick,, I'm going to say that they are being held in place by the ash that has settled between the bricks ?? On my 'Big Bertha' boiler,, once I remove the first brick, which is a battle,, then the rest of them loosen right up and come out easily.. I can't see any reason to glue them in,, the pressure of the coal against them hold them in place.
Without seeing the new lid, the old and new hinges I can't comment on the hinge/lid replacement,, maybe you could post some photos... I will say that the only way that lid go warped was if the seal around it's perimeter got old, compressed and leaked air past the lip, and into the hopper.. If air is drawn through the coal in the hopper, the fire will travel up into the hopper... so make sure it seals well.
This stove may be an earlier model before a multi speed blower was offered,, you can get motor speed controlers at HomeDepot and Lowes.. give that a try..
Matthaus recommened Duplicolor high temperature paint to me when I rebuilt my AA boiler,, it has held up very well, so I'll pass along the recommendation. Any of the high temp paints will probably work very well, and most don't recommend a primer.. Duplicolor 1200* BBQ flat black has worked well for me on other stoves..
hope the above info helps.. Greg L