The bullet in the response that is standing out to me is:"(7) The accessory dwelling shall not be a short-term residential rental, as defined by City Code section 3-2-152(a)(2), for a period exceeding 120 days per calendar year."

Short answer: Yes, laundromats can be profitable, but profitability depends on a few factors.

It does eliminate the need to add chlorine but the chlorinators (Pentair IntelliChlor) have a fairly short lifespan.  

I said no but it maybe cost you 50 bucks a month other wise your tenant is paying off your principal and 3 to 5 years goes aweful quick then you own it free and clear and you just put 10% down and tenant paid of the rest what are you really going to do with 100 a month anyway... it was funny that was a hard sell. but I can tell you I did about 50 of the no interest and as they paid off you talk about a happy buyer getting their reconveyance deed in such a short amount of time.. 

A lot of my clients buy in Alexandria because of the strong rental market and laid back laws on short and midterm rentals. 

:-)BTW, I'm actively looking for working partners with some cash to put in for the short to mid-term.

Quote from @Spencer Elliott: Long story short, land is on loan and I’m purchasing a manufactured lot as a temporary home/future ADU to my final build.

The only exception might be if you plan to and if your market supports short term rentals.

In short no change.Cash flow that was supposed to start in 2019, will now start "in a couple of years". 

I would think with the HELOC, I could run with that until I can do a refi and with the interest rates starting to come down, there should be some gains to be made and I can repay the HELOC in short term.