Hey Dave,My newly refined understanding is that your step up in basis would occur at the time of your spouses passing, so 2019.

I would be interested to hear if others have had similar situations occur. 

I built my own website in Wordpress using a vacation rental template that I bought for about $20. 

When you subsequently transfer the title to an LLC within the same year, it will typically trigger another reassessment.This means you are likely to face two property tax reassessments: one when you close under your name and another when you transfer the title to the LLC, even if both transactions occur within 30 days.

or only if an audit occurs?

You stated, foreclosed, so it implies the public auction occurred and that the auction now is an attempt by the owner to sell an REO.

The only difference is the seller is behind on payments, which is irrelevant if the sale covers all the debt and can occur before the foreclosure sale date. 

The 5 unit building was vacant and only about half renovated so it’s been a total lease up which has also occurred much faster than any other building I have because I have very little turnover typically.

Capital calls can happen to extremely experienced investors (including multiple gurus that I follow) when unforeseen circumstances occur. 

As long as the gain you incur from the sale of your property AND the investment with bonus depreciation occur in the same calendar year, it's possible to defer all of the tax exposure you would otherwise have.