We did get much lower costs when we changed to minisplits but the initial cost is high.

I talked to several insurance brokers and they both said majority of insurance companies do not provide coverage on homes with knob and tube wiring due to potential fire hazard.

If you sell for $460k and it costs you say $30k to sell, you net $430k.

Do you think it's better to start sooner with a cheaper property to get in, or potentially wait longer to save more? 

They do an inspection, look for potential costs with repairs and produce a final report.

I've been running the numbers on different properties using a variety of online calculators for properties that I initially thought looked like there may be potential.

You will have to gather more accurate operating costs (vacancy loss, taxes, utilities, insurance, mgmt fees, maintenance, HOA) to best determine potential future performance.

No if potential buyer have given you emd than you are under the assumption this is a serious buyer and will close on the deal but he has only a certain amount of time with his inspection period so if he backs out you still have time to fund another buyer. 

Any kind of non QM financing will have higher closing costs compared to conventional.

If you don't do that, once she passes it will go to probate court and it can cost a lot money.