However, given that residential real estate value is based on ARV, I am struggling to find comps on a rented 3 fam property that seems to be under-performing.

If you can't perform, I'm not happy but at least I get my EM back.

How do you go about finding a reputable TK provider who can actually show better than stock market CoC performance?  

I might push harder with them to get a denial, based on the new information.Ultimately, it seems that you did not perform, so you may just forfeit your deposit. 

It wont perform like an 80% leverage property because it isn't.

What you are trying to do is assess how well the location is performing for them and then compare that to their typical national average in rent they pay per sq ft and their AUV (average unit volume) nationally. 

Hope it is a great performer for you!!

Yes, there are lazy brokers/agents, just like any industry there are stand-out performers and those that think it's going to be easy.

I'll add:Charging Late Fees on re-performing loans and keeping half for themselves.   

They don’t give a lot of weight to what you think the performance will be.