how to randomize specific things in a custom structure

for example vine placements, or specific block replacements (eg. cobblestone to mossy cobblestone, to name a vanilla example) for derelict structures where one can clearly see that they have gone decades, if not centuries, without renovation. maybe also that the ceiling collapsed at a random point. or even half of the structure is missing. is that possible, without creating a different structure for each?

(Maybe also that it spawns smoothly on the ground and not half of the structure is floating above the ground, is there something I can do about that?)

Thanks for any help!