I'm having a problem finding a service person that really knows these things. I happen to know that conversion and ignitor parts are available, affordable and that there are few moving parts. I'd like to clean-up two ...

What you do is let those "seed" properties appreciate, because you bought strategically, so let time do it's thing and prices ascend to where gravity is pulling them.

CoverMyMeds is building their $240,000,000 headquarters there, gravity just announced their phase 2, and Mount Carmel West is being demolished for redevelopment. https://docs.google.com/document/d/1aSKpAug4JZxYIvHzRotL36OPHjlahTiOPbZ0Xz3ijMM/edit?

Others will be happy with a standard gravity fed more in that $10k range.

Even standard gravity systems you should only plant grass over the drain field. 

Franklinton has been seeing lots of developments like the completion of Gravity Phase 1 and phases 2 and 3 on the way.

CLE has the same type of 100 year old money pits that Akron has-- I like gravity furnaces, they are inefficient af but they don't have hardly any parts to break, galvanized plumbing supply lines are a nightmare, cast iron stacks will be at the end of their useful life.

Familiarity with gravity forms helps.

Attorneys have tried to put the breach of the duty of care into mathematical terms whether any action or inaction was negligent by using the BPL analysis:B=burden (cost)P=probability of lossL=gravity of lossIf the BP>L, then you are likely negligent.

Same with septic - are these aerobic or gravity systems?