Be sure to verify!

A modest markup on material will insure they are still in business the next time you need them.From my position now as a landlord/investor I will work with labor only contractors for smaller stuff but I expect I will need to provide a certain amount of supervision during and verifying after completion.

What documents do they require, what credit scores do they allow, how do they verify previous rental history, etc.?

Be specific and give verifiable numbers.

That being said, most lenders will require at least two years of W2 tax returns to verify income and assess risk when granting a loan, so acquiring finance may be complex. 

Verifying last 2 years of rental history very important!

What documents do they require, what credit scores do they allow, how do they verify previous rental history, etc.?

What documents do they require, what credit scores do they allow, how do they verify previous rental history, etc.?

As long as your opt-ins are legitimate and you are able to verify the number you're sending from, you shouldn't have any issues: https://www.webfx.com/blog/marketing/sms-software/

BiggerPockets is not in a place to verify the truth or falsity of these claims.