Asset protection comes in when your asset worth is in the 7 or 8 digits - at that point you are becoming a target for frivolous lawsuits.If you buy a duplex and you have 50k in equity and the rest is financed (what @Joe Villeneuve says!)

I can pull out around 25,000 in equity on a refi.

You now have $40K in equity you can draw on.

I think I may have around 275-300K in equity there.

This way you can continue investing in equities and also gain the option to invest in real estate.

The reason I structured it this way is by holding onto the profit from rent ( mortgage payment is 3579 on 665k ) and my regular payments I will have prob 200k in equity ( purchased at 740k) and total rents are 6900 a month.

I appreciate you pointing out the 4.5 million in equity.  

.— (a) There shall be exempt from forced sale under process of any court, and no judgment, decree or execution shall be a lien thereon, except for the payment of taxes and assessments thereon, obligations contracted for the purchase, improvement or repair thereof, or obligations contracted for house, field or other labor performed on the realty, the following property owned by a natural person: (1) a homestead, if located outside a municipality, to the extent of one hundred sixty acres of contiguous land and improvements thereon, which shall not be reduced without the owner’s consent by reason of subsequent inclusion in a municipality; or if located within a municipality, to the extent of one-half acre of contiguous land, upon which the exemption shall be limited to the residence of the owner or the owner’s family;Florida statutes provides:(1)(a) A person who, on January 1, has the legal title or beneficial title in equity to real property in this state and who in good faith makes the property his or her permanent residence or the permanent residence of another or others legally or naturally dependent upon him or her, is entitled to an exemption from all taxation, except for assessments for special benefits, up to the assessed valuation of $25,000 on the residence and contiguous real property, as defined in s. 6, Art.

We raise capital in equity to expand our real estate portfolio.

That leaves the buyer with $36k in equity for reasonable ARV.