You only pay on it if you withdraw the money.

When you sell, how is the money divided up? 

I currently have saved a lump sum of money...

I use the Zelle app to collect upfront money from tenants and it is instantaneous with no take backs but it is not automatic so I doubt you could set it and forget it.

if you are looking to get out of the 2nd job and get some time back being a hard money lender or other "money man" part of a deal is about the most passive you can be.  

Owning a property with the sister is about impossible as she is not good with money or business minded.

I would rather spend some front end money now and do a relocation, then be able to use simple side-by-side units than to be forced into stackables or all-in-ones.

You can offer them cash for keys-give them money to move.

Given your question however, I get the sense that this might be your first time managing a project like this and so would strongly advise that you connect with a General Contractor that you can trust as it will end up saving you a lot of time and money over doing it on your.

It seems like banks lend more money to people paying more income tax.