Overall I would treat this investment as a high risk gamble and willing to accept loss if it failed but It's also a very interesting process to understand how the industry works.

Is there any websites or platforms that I can add to my knowledge that help with this diligence at fair/free cost?

You could borrow a second against the $400k of equity in your property - and accept short term negative cash flow to earn a lot more on the great deal you don't want to pass up.  

That means you can distinguish your listing by being responsive and courteous while providing a quality product.To more directly answer your question, while there isn't a great website for MTR data, I do estimate MTR rents with either the BP rent calculator or rentometer.com's and then multiply by 1.5x as a screening tool.

I don't like that their website only talks about "project level returns".  

Just needed to blow some steam off in the group.All 7 of my accepted offers have fallen apart at the inspection phase.Each time we find an expensive problem in the inspection and the seller is not willing to make concessions.$3K spent on inspections with no house to my name yet. 

I have had a few very small problems with using this company's website to place my orders.

My tenant just let me know they accepted a new job in another town and will therefore be leaving us. 

I also appreciated @Scott Mac's perspective regarding liability and accepting commission as that could be a slippery slope.Ultimately on 50 units, you're talking about $250 per month revenue. 

Not sure is seller will accept an offer with these contingencies as it will cost time on the market if the contingencies are exercised.