Many months of costly vacancy, local market rent & resale deteriation, special assessments, property taxes and maintanance fees suggest a quick sale would have been the wise thing to do 2 years ago.

I tried the Reia and it's basically a giant sales pitch

Utilities included.Fully rented.For sale off market.

Also know that upon sale sometimes the presence of more water meters increases value.Curious to understand the forum's opinion on the best water meter configuration given costs OR if it’s just not worth it and I should leave the one master meter and stick with RUBS on all 4 units.

Figure out how many sales you need to break even.

The other part sounds like it was a rehab and now held for sale, which does not qualify for 1031 Exchange treatment. 

Typically single family because the price is driven more by the sales comparables vs the rent amount

Welcome to the European tax environment :-)The US does not have federal sales tax, but we do have State sales tax and City Sales tax.

Here are the specifics on our Seattle house: 5br 4ba 3,400 sq ft, built in 2019, $1.7M est sale price, $5.5K-$6K/mo est rental value, 4.0% mortgage with $3.3K monthly payment, around $1M in equity. 

I have a tenant occupied single in Allentown for sale.