I have interviewed a couple of services, but I am not having any luck finding a reliable and affordable company.  

I personally feel like carpenters are one of the most mysterious and aloof people out there...Anyways, I request a lot of bids for each part of the rehab process and along the way I've found some pretty great people that are cost competitive and provide high quality work.For example, I can provide some pretty solid recommendations for:Egress windows, electrician, window installation, storm doors, flooring (carpet/vinyl planks), hardwood floor refinishing.I can provide contacts for other jobs like carpentry, drywall, etc. but the ones listed above are the best of the best.I've found it pretty challenging to find a reliable handyman and carpenter.

You can also network with wholesalers and Realtors and continue to bring value to them and be a reliable buyer when the time comes to close on something. once you have some momentum there, make sure you have a game plan for financing.

Census data, but it is not always reliable and current.2.

My philosophy with contractors (in the past) has been - "hire the right people and stay out of their way".I need an honest, reliable, cost-conscious GC who can pull permits, demo and knock this "fix n flip" out in 3-4 months.  

HML are big on reliable investors with good track records, so as you do more deals and build your track record (preferably with the same ones), you might eventually be able to get close to 100% financing.  

They are also pretty low risk as they are rented to reliable and high-earning tenants. 

The most reliable way is to use recent (max 6 months old) comps.

What advice can you give a newbie like myself that just wants access to quick, affordable, reliable information?

Best and most reliable way is to build your own list, any other list will already have been scoured by investors in a market like this, especially if you don't have a competitive edge on the flipping costs.