This is very frustrating as they have both wasted 1 month of my time before communicating this requirement.Am I doing something wrong or I just haven't spoken to the right lender yet?

A couple of great books for you to read/listen to as you build your network are Sales Ninja by Larry Kendall and 7 Levels of Communication by Michael Maher. 

This PM LLC will lease, communicate with tenants, maintain/repair the properties etc  I know I need to add this PM LLC as additional insured on the rental policies but do I also need to have a separate policy for the property management LLC?

As for what you can do to vet these people who are contacting you, before you communicate any further with them (and certainly before you consider doing any business with any of them), read these posts and learn how to spot the scammers and fakes:- Should I be worried about my DTI?

Hi Ross, do you need this person to communicate a message to the homeowner or just someone to drop a flyer by door? 

Perhaps you can find a “net PM” for 10%, which, in this scenario, would equal a 6% “gross PM.”But I don’t think the numbers really matter in the end, because two potential outcomes appear to me right away:1 - Unless you will have a way into the PM’s maintenace request system or for the tenants to communicate with you directly, you may soon start to have higher vacancy due to tenants who may have leaky plumbing appliances that keep them up at night, tree branches that hit their windows in light breeze, garbage piled up around the dumpster, broken irrigation sprinklers, and the like.

All paperwork and communication to both seller and buyer was handled professionally.

@Angel GutierrezIt is also about the messaging- what you can communicate to a buyer.

He does good work and communicates clearly.  

"In writing means communicated in written form with proof of receipt" which means also including any method that you can proof in digital, based on my knowledge.- realtor not a lawyer, formal expression please consult lawyer