I know that the city has been consistently growing without missing a beat in past 30 years, vacancy rate is 3%, rent price was increasing in past 20 years, unemployment is consistently low at 3-5% at past 20 years and so on. 

You would be looking at a rate in the low 8s based on your credit score. 

If you can definitively prove that the seller intended to deceive you about the square footage for their personal gain, you may be able to take legal action, but probably low chance of success considering you had ample opportunity to measure the home or get an appraisal with measurements prior to closing, and had your chance to negotiate the price based on square footage and all other factors prior to closing. 

You never get a guy to show up first thing in the morning for a heat call.

Looking to acquire (initially) small, 2-4 properties outside of CA; focus on low-tax, high growth markets (e.g.

The market here is extremely difficult to enter due to cash offers and low inventory.

Even if you get nothing, you are helping out your fellow landlords by getting it on record that they are low life tenants. 

The first unit has ~75% occupancy but mostly because I take it off for a few weeks in low season to go through everything, fresh paint, etc.  

living I desert ac units is what we primarily do so when hit with so much on heating wasn't prepared

While still technically in seller’s market territory, inventory is well above extreme lows seen in recent years and has held steady for many months now.