Ideally, you figure out how to manage the house well and can screen tenants not only for the ability to pay, but the ability to fit into the eco-system of the community you've built.I'm looking to expand this strategy further as I think the returns are insanely high and worth the management. 

I’ve read many replies about not using lock boxes because of the risk someone trashing the property, stealing items, putting the home up for rent after knowing the code, losing the keys, not putting keys back in the box, you want to see/get a “feel” for the type of person they are, etc.People also recommended ways to prevent this by requiring photo identification of anyone viewing the property and only giving them the code once they have arrived at the property.It seems that if you had more than 3-5 properties that you are managing or listing it would be an enormous waste of time and maybe impossible depending on the location of the properties to meet every screened/prospective tenant at each house.

They also don't have a open API which means you can't syndicate with other software's like tenant screening automation, etc as you grow.

We don’t know any PMCs to recommend in the area mentioned, but since selecting the wrong PMC is usually more harmful than selecting a bad tenant, you might want to read our series about “How to Screen a PMC Better than a Tenant”:https://www.biggerpockets.com/member-blogs/3094/91877-how-to-screen-a-pmc-better-than-a-tenant-part-1-services-and-processesWe recommend you get management contracts from several PMCs and compare the services they cover and, more importantly, what they each DO NOT cover.

Also please help me with the other required pet related prerequisties (like vaccinations history, behavioral aspects etc.) that landlord needs to be make sure while screening tenant with pets.

If I answer one, it will lead to another, and another, and another.Your best path forward is to read a few books so you have a foundational understanding of what a good investment looks like, how to find them, how to purchase them, how to market them, how to screen applicants, and how to manage the day-to-day issues that pop up.

And yes you should always screen your tenants.

It is removed now and I will screen tenants the same if they accept it vs if they do not accept it.

Also, make sure you have the minimum screening criteria highlighted in your listing so you avoid these types of applicants moving forward. 

You need to establish your screening criteria, and apply it in the same manner to ALL applicants.