here're some tips to beat the bosses (madhouse mode)

[Der Großmann]

Jack Baker (garage fight)
rocomended gun : none (do not shoot)
environmental : when he finishes off the cop rush it get the lockpick and unlock the box to get the car key ,do not start the car right away ,lure the boss to the other side of the car so u can quickly get in and start the engine (once u started the engine he won't pull u out.
Jack Baker (round 2)
recomended gun : none (no shots needed)
simple use the pillar in the center of the arena to avoid him for a while and he will throw his weapon and go for the chainsaw ,do the same
Margueritte Baker (round 1)
recomended gun/s : flame thrower and (or) pistol with enhanced ammo
when u see the flying insects (the big ones) just crouch and stand up (repeat) by doing this they will have a harder time hitting you
mutated Margueritte Baker :
weak spot : crotch
recomended gun/s : Magnum ,Granade Launcher (flame rounds) , flame thrower (try avoiding overusing the shotgun)
Barn fight :
2 enemies
recomended gun/s :Magnum ,Granade launcher
use the haze and circle around it while unleashing hell to the creatures' head
Mutated Jack
weakspot: eye balls
recomended gun/s : shotgun ,granade launcher (neuro rounds) and Magnum
take the fight to the arena's lower level for better mobility
E 001
in this fight u don't need to shoot that much
recomended gun : shotgun
survive until (in classical RE manners) u can get ur hands on Albert's Magnum to finish the battle