The common solution is fedexing doc.s, and having your signature notarized at the local US embassy/consulate.  

A strong valuation and even pre listing appraisal and/or inspection can sometimes be a worthwhile investment but not a necessity. 3-5% commission for what is effectively commercial property is common. 

First time encountering this scenario so I appreciate any advice

The most common one is that when we get a new lease signed we are not getting the rent roll populated. 

Common fees will include a set-up fee, a leasing fee for each turnover or a lease renewal fee, marking up maintenance, retaining late fees, and more.

This is common.

This is just me brainstorming ideas based on the scenario you wrote.

It is very common to see a portfolio loan with a higher rate, a shorter term, and maybe even be an adjustable rate – and sometimes all 3 of those.

I'd rather trust that someone pay an assignment fee (based on your word of mouth referral) and not get paid then the other scenario. 

Is this common practice to close a deal?