The very first kill scene shows a person's body bring torn in half, but the way it was executed would nearly impossible. 1) The torso is the thickest part of the body; the shoulder and hip joints would give way first. 2) The white cotton ropes used to anchor the victim to the tree were far too flimsy; they would stretch and snap first.
The publicity photos the characters find in the old mansion would have yellowed and become stiff and brittle after the approximately 60 years since they were printed. These were advertising materials, and not archival. The photos they handled were new, not decades old.
The clothes and the mansion's carpets are all clean. After many years in an abandoned building, they should be very dusty at the least.
A man in his 90s would not be physically capable of doing everything Hayward does in this movie. He has no trouble performing dexterous acts, and seems to exhibit superhuman strength.