Depending what your debt and basis is in your current investments, depends if you do a simultaneous disposition (1031 exchange) and move your funds into an investment that meets your goals and improves your position. 1.

I am doing a 1031 exchange (nearly simultaneous, closings 2 days apart).

This requires a double-closing or simultaneous closing (dry or not doesn't matter).

I have a contract I am selling to a friend that would like to do a double or simultaneous close versus an assignment (could be dry closing, but not required).

Everything seemed impossibly cheap (coming from an unreasonably expensive market), but the rents seem simultaneously too low (to cash flow) and too high (for the ever lowering BHA).

You cannot have multiple FHA loans simultaneously. 

@Salomon W.I have never done this but for what you are thinking you can try to do a double closeFirst of all I don't think when the lender closes that there can be a second lien with the sellerWhat I m suggesting is you close with the lender with you full downpayment and simultaneously or right after close with the seller with the funds given back to you as a form of a second lien/mortgage..

Different parts of different codes sections all apply simultaneously on one tax position.  

Also, to answer your last post's questions: yes, you should be able to simultaneously manage your rentals and clients assuming you are within regulations. 

But don't let that stop you from starting the process and making offers simultaneously.