I set up some marketing and lead generation, and I fell on a lead for a million-dollar property. 

If multiple story, look at the walls and see if any fell. 

Hi, we already submitted an offer letter today for a 4-plex asking price $310k (2beds 1 bath) and we are the 1st one to offer them after the previous buyer's financing fell through, the seller agent sounds promising. 2/4 tenant contracts are inconsistent with dates and the seller said that he lives in 1 of the unit which is not consistent with contract dates.

This implies the cash flow must recover the negative position before you have legit cash flow.I had an offer on a property (at the start of COVID when prices initially fell) that I was planning on adding an ADU and maybe later a JADU (if the OO rules changed).  

I have some very bad tenants who are not only not paying rent but they are bringing all kinds of trouble to a very nice residential street.. subleasing my house where my lease clearly states no subleasing of any sort - They already acknowledged while I was away for a year due to Covid they had brought in another person who is not on the lease and I never approved off to live there permanently..They are bringing in prostitution!

Hey Jay,As a fell CA native and buy and hold out of state investor, I can empathize with your current state of affairs. 

Now my credit score fell to 665 at Equifax where my other bureau scores are over 800. 

The property's last offer fell though and it is back on the market.

His previous (perspective) buyer's financing fell through at the last minute, and I was able to close the deal within a tight schedule.

It got her current at that time but she soon fell back into not paying after that.