There is a language barrier.

They may contain language on dealing with live-in maintenance employees.

You should have language in your lease that covers this As far as a rent credit, that would be up to you dependent on what needs to be done and how long  for the leaks, mold, window etc...Always good to check CA landlord tenant laws.

You can do it this way but be careful with the language.

Loan terms are negotiable but the legal language is pretty standard.I am sure that an attorney will use the right form that is in compliance with the state law and to make sure that you have no issues if your borrower stops paying and you need to foreclose.

In simple language, when seeking approval for a loan, will only my income and credit score (which is excellent by the way) be verified or my household income count?

@Matthew Paul and @Rhett Tullis - no language specific to the situation in the lease...

I am in downtown manhattan and speak 3 major european languages besides English!

You are bound by the term and language contained in the lease

Make sure to review the current owner's lease agreement with that tenant to confirm there is a security deposit and see what type of language they include regarding the security deposit.