Some have more than $1 million in equity while others have less.4.

Moonshot for sure, but interesting question.Conceptually, you need $5M or so in equity, otherwise you'll be overleveraged.

Or you could refi and only be into the property for 25k and have 150k in equity with a lighter cash flow. 

Option 1a COULD be ok, but only if you can spend that $20k and add more than $20k in equity prior to sale which is no certainty when you're starting with a rent ready property.

Concentrate on making first the hundreds of thousands in equity (owned equity, not financed property!)

What you do bring in equity from investors.  

My wife and I are currently starting out real estate journey. 1.5 years ago we bought a dental practice, and last year we purchased our dental office building priced at around $2M with $500k in equity.

Even if you borrowed 400k against it now, you'd have well over 500k in equity in 10 years (500k plus the principal paydown).To me, I think you refi it and pull the money out entirely tax free.

(It was sweet deal and the (ARV) I will have about 300k in equity to tap in on)

You hope either (1) neither lender finds out and or (2) neither lender decides to take action if they find out.Second, you make up the difference in equity with either (1)cash (2) 2nd mortgage loan with the owner with less equity giving to owner with more equity and/or (3) trading something else of value, such as another property, car, RV, etc.