How were you able to build up the amount of cash in order to put down on all 4 houses?

We are using our funds at this time to get us on our track to build up our Business JCT Properties.

@Andrew FredricksonSFR right now while I build up capital.

you can fix up the multi doing some hands on work, and gain experience as a landlord while your build up your portfolio 

You will find other wholesalers at these events as well as cash buyers so you can build up your cash buyers list.

That's good advice.I was hoping that over the next 10 years, I could acquire some income producing properties and also build up some equity in those properties.

I think it makes a lot of sense to solidify your PM skills as you build up your own portfolio, and then take those skills to the market as well. 

Do you want to build up a big portfolio, or build up a lot of 0's at the end of your bank account?  

Since this would be my first rental property (and first property in general), is it best to put 20% down and use the rest your money to fund other RE investments or pay it off in cash and build up from there?

even if the ink is still wet, you wouldn't be able to be sued if an accident happen