Fico while they will look these are not credit score driven loans like those buying rental houses or houses to live in...

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

;however, my issue is that I dont have good credit and since im self employed I make.very little income. 

Thats your bonafides to being able to do future deals.As mentioned above, keep your credit perfect.

I have done small things like switch from glass wine cups to acryliic ones that look like glass and take a damage deposit of $250 that helps mitigate small things breaking that are over $50.

Insurance protects your property from paying out of pocket for damage, plain and simple.

For me as well as the seller.First, you have to define Sub to financing.Do you mean the reckless kind where you overpay for a property, take over the financing and borrow from others to cover closing costs and holding costs when you have no money, no credit, no income, no reserves and can't tell a warranty deed from a deed of trust and you close on the kitchen counteror do you meanbuying below market value, already having a nice income, having reserves, using escrow and title, already understanding the due on sale clause, have done a lot of creative purchases and know when to use and when not to use creative finance and how to recover if something goes amiss?

@Martti Eckert here's the big issue that no one really talks about that you hopefully find helpful (this is copy & pasted):-----------------------------------------------------------------------------------------------------------Recommend you first figure out the property Class you want to invest in, THEN figure out the corresponding location to invest in.Property Class will typically dictate the Class of tenant you get, which greatly IMPACTS rental income stability and property maintenance/damage by tenants.If you apply Class A assumptions to a Class B or C purchase, your expectations won’t be met and it may be a financial disaster.If you buy/renovate a property in Class D area to Class A standards, what quality of tenant will you get?

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

The mortgage will also stay on the seller's credit which might create an issue when/if they try to purchase another property.