“Box 1” passive investors – Passive investors who receive a K-1 with income in Box 1 “Ordinary business income (loss)” will have QBI.Realtors and other professionals – Definitely a trade or business.

For example, someone could be at 0% capital gains rate gain deferral doesn't seem to indicate you can offset ordinary income.

1) There are ordinary/W2/active income on one side.

As soon as you convert those into a flipping business of any kind you'll move into ordinary taxation of your profits. 

I am not a CPA - but the IRS treats income from flipping as ordinary income (not capital gains).

The blue pill creates a contented experience of ordinary reality.

On the S-corp side, you will have negative ordinary income offsetting your employment income.

All income from flipping properties is ordinary income and subject to SET. 

But, make sure you set aside the amount of SE taxes and ordinary tax you will owe on your commission when you file your return. 

In general, the active members will be subject to Self Employment tax as well as ordinary income tax and they should pay estimated taxes to cover this if they have no coverage elsewhere.For the "silent" partners, this will still be considered ordinary income for them, but they *may* be able to avoid Self Employment Taxes.