And that’s if you can’t find something to buy for under $100k or time multiple sales at once. 

It seems like there is no catch, would they let me buy a property this month and a property the next month for instance if I have the 25% down+closing costs and can prove that it rents for a decent amount more than the mortgage?

Did you buy this property on your own or did you partner with another investor?

BiggerPockets also has a calculator to analyze deals, and I highly recommend you start this as soon as possible, even if you are not ready to buy.

Leverage  anything in the US  so you can  use the cash to buy in CR  ( US home / 401K / other assets ..etc)  ...pura vida !

I am new here just trying to learn and gain knowledge to start buying my own rentals 

We have made money buying properety based on cash flow (lower priced) rented out for a period, then selling to an owner occupant. 

If you wanted to do a 1031 exchange down the road to use that equity and trade up then that'd be a good idea.The homes I’m looking at buying are in the 330,000-350,000 range.

If you buy in a prime location with desirable amenities, you’re setting yourself up for steady income and long-term growth.

Since your an estimator are the materials and labor based on facts (i.e. hard costs a labor units) or a guess.Nothing personal but I wouldn't consider anything you wrote there, if I was buying I'd do my own estimate/SOW.