Have a few conversations about your situation in general and start there! 

@Colton BridgesAre you looking to refinance before or after the fourplex conversion? 

Stanley - I would suggest that you go have 3-5 conversations with lenders and understand how much they are willing to lend to you given your financial situation.

The zoning and Philadelphia Historical Commission approvals have been obtained, and building permit has been approved for the building renovation/conversion now working on building permit for the rear addition.

Conversely, if one side of the house sits on unconsolidated fill or on silt, it would settle or shift over time - once again, causing cracking.

Advice on Layout/Design: For those who have added ADUs, do you recommend standalone units, garage conversions, or a combination of both?

If you're pulling a permit already for plumbing changes, just get the permit for the room conversions at the same time.

Just wanted to revive this conversation: Any recommendations on one versus the other? 

If they are legit and you don’t have any other offers then I’d have the conversation with them but I’d want a higher than normal down payment (ideally 50% or at least more than the normal 20%), a higher than normal interest rate (at least a point above the prevailing rate so like 9-10% right now, but you can structure it as interest-only payments so their monthly payment is still lower than conventional), amortized over 30 but with a balloon in 3-5 years, something like that.

I have lengthy conversations when tenants move in about letting us know immediately if there is a clog, to stop using the plumbing if things are leaking, that they will be responsible.