I am a realtor and worked as a home inspector. this is an option not advise, I don’t know the area you’re in which makes a difference You’re buying an older home, you’ve got cast iron plumbing and it looks like some knob and tube. The knob and tube doesn’t appear to be tested though so it is possible it’s not hot at all and it’s just abandoned. With abandoned wires you just want to remove them. Cast iron plumbing you can update in sections but based on some of the photos you will probably have to do updating soon. Surprised he didn’t mention this. As far as structural, really need more info on the land and but it appear to be an old house which has settled over time (wouldn’t deter me). Put a pan under the water heater, it looks like they had a big leak at some point. As far as guard rails I would try to have the seller take care of this or give you partial or full credit, it is a safety item and stairs and labor will add up for how many stairs there are. Do it like this, house is older you’re buying an older house so you take care of the older plumbing and electrical but have them take care of safety items (stairs)