I warned them not to flush anything except toilet paper, because of the risk of clogging the plumbing (since a lot of people are having trouble getting toilet paper). 

I've never heard of or seen that plumbing in the link.

Hi Denise,My husband and I mostly likely will be buying a home with the same situation.. do you mind sharing how much your kitchen + plumbing ended up costing you? 

One of the properties is currently rented for $1200 a month, newly renovated as of January this year that I did with my own two hands and only subbed out the landscaping and the upgraded plumbing, and valued at 80k (clearing $940/mo after taxes and insurance) Link to pictures and video walk through https://drive.google.com/open?...

After this was done we put down 14mm plastic under the house as a moisture barrier.We dug a French drain around the front of the house back to the creek to help with any moisture issues under the house.While we were under the house we also replaced all the plumbing with brand new pipes.Both bathrooms have been completely renovated with the master getting a full custom tile shower and the other bathroom getting a soaker tub with custom tile surround.

It needed some minor plumbing work and brush cleanup around the house.

(depending on what your ideal buyer finds desirable)  Then,... other than the desirability and the numbers, what is the risk involved.How likely is it that there is a foundation issue,  if you open up a wall, will the town have you redo the entire damn plumbing an electrical.Is it a flip, or is it a buy and hold,If it is a flip what is the ARV, and how long will it take to fix the house up and how risky is the scope of work?

Money can help you ride out a downturn, money can help fix the plumbing issues you weren't expecting, etc. 

Then I also had to get town approval for more parking spaces, and had to hire an attorney for that.In the list you have , I don't see anything for elec / plumbing permits, or inspections. 

You still need to run plumbing and electrical.