And since you'll have 20 income streams you can replenish it faster than with a single property.  

Whenever you use anything out of the budget you suspend taking cash out and replenish the budget.

Since then, I've recieved a new job and am making significantly more money, so replenishing an adequate reserve is my top priority right now to avoid this mistake in the future.

MOst of them need HML to replenish their cash.. so they can't wait 6 months for a title co to write title insurance. 

And than, if doing it smart, we get a line of credit, say $500k, that we can just grab as cash whenever, to secure more properties as all-cash offers, and once closed our lending partner will just finance us out and replenish that line of credit.

We have learned alot within these past few years and it would probably take me another 1.5-2 yrs to save up to $50k again with our initial expenses, or if we sell we will replenish our cash savings, plan to buy more property, not utilize all of the money from the home sale, maybe use 50% of the cash received from the sell of our current home to build a portfolio, and lock the rest up as a cash emergency on stand by maybe 20% and the other 30% long term hold for long term growth.As for me I am a "bet it all on red" kinda guy but my wife is much more conservative and the smarter of us 2 although I am the engineer lol.

I would suggest you do everything you can to force replenishment of said security deposit as it is not returnable until about 30 days after they move out in undamaged condition. 

I'll have a 20K bonus in November that will replenish that plus I'll be setting that 20K aside towards current mortgage, car payments, insurance in order to effectively reduce my monthly expenses by $1600/month.

The cash flow in the mean time eases the pressure on your reserve because you know how quickly you can replenish it.

He will borrow money and pay rent by Friday the 18th.I picked 3 because I doubt that the security deposit will be replenished after either option 1 or 2.On Friday I have the rent in my account.