I build from ground up or do heavy rehabs in the DMV area.

You will use conventional or FHA, but it's VERY hard to win in Northern NJ with an FHA loan on a multi just because most sellers interpret FHA as not having the money instead of an investment vehicle so that needs to be explained.You aren't going to learn much in an online underwriting course as most of those are for commercial properties and no one online can teach you how to underwrite a small multi in Northern NJ because the vacancy, cap ex, taxes, are all different.

Would a SD401K, SDIRA, or SDHSA work as an asset protection vehicle?

Ft)Heavy Cosmetic ($55-$65 x Sq.

The problem is I'm not cash heavy at the moment.

Multiple, billion dollar companies are investing investing heavy in our area, such as Intel, Google, and Amazon.

you looking for a vehicle to reinvest it or just wire from bank to bank?

On top of that, since Orlando is a heavy appreciation market anyway, cash flow is always on the lower end compared to areas like the Midwest US.

Here in Charleston, in order to apply for the legal residence tax assessment ratio, all owners have to provide copies of tax returns, utility bills, driver licenses, vehicle registration, voter registration, and the settlement statement/CD, along with an affidavit stating that all owners occupy the residence and do not claim legal residence anywhere else.

The lender will probably also want you to have an LLC as the purchase vehicle for this.