All the engines you listed have 4 bolt mains, forged cranks, forged pistons and forged rods. All GM parts.
454mag, 502mag and HP500 all have GM rect port heads.
454mag and 502mag have 2.19/1.88 valves
HP500 has 2.25/.1.88 valves
525efi uses Edlebrock aluminum heads. Not sure of valve sizes, probably 2.25/1.88's
Piston Pins---I think are pressed in on all, but not sure.