As far as just sealing it up where rodents won’t get through you could even use the side of an old plastic tote cut to fit with a little silicon around the edges to close it off.

hey just some advice from a plumber ive been doing plumbing for 5 years nowyou said you had a iron sump pit, likely the pit is beginning to corrode and thats the cause of the iron deposits, now a days most pits are made from composit plastics ,another possibility is the piping could be the cause if its a metal pipe [iron or galvinized steel ] it could be contaminating the water being pumped out, again most pipes now a days are PVC either sch 40 ,80 or ABS to prevent this issue, it could be the pump is corroded and failing but if its working i doubt that its that ad if the pump was that bad it likely would have failedother than those the only other thing that comes to mind is that it could be something in the basement that is made of iron or steel that is in the pathway to thw water on its journey to the pit.hope this helps

Yes, you can charge them, and you can sue them, but you can't recover 100-year old woodwork original to the home if someone decides to tear it down and replace it with new plastic foam board molding.

Then they started unfolding this great big heavy duty plastic bag. 

Plenty of room for hosting in the backyard/patio as well. 

Mine did too at first, but reality set in after a few months of washing dishes in the laundry sink, and having plastic hanging in the shower, her enthusiasm waned.I'm not suggesting you don't do it, just pointing out that the idea of it and the reality of it are not necessarily the same. 

The next major issue is permits, I don't like touching anything that has a converted garage or patio let alone 4 jerry rigged bedrooms, the assesed value isn't necessarily an issue depending on the state especially (In CA there are $2M properties assessed at $200k because of prop 13)  Investors will see the real value but the other issues would have me concerned.

Light bulbs on back patio. 

While there may be a chance of something under the patio, I’d figure it’s highly unlikely if there are no remnants of supply lines or fill pipes.

Now, we're not talking an 18 foot deep high dive pool down there...it might be 1" - 2" deep (but, I'm still trying to decipher the photo from my inspector and get a hold of him).It also (oddly) looks to be on top of a sheet of plastic.