The interest income from a loan payment is regular income, not capital gain no matter how long you have the note in your portfolio, and this is why I buy notes in my SDIRA for my personal portfolio.

My question is, what should I look for in seller financing, ask about, avoid, would I use the same PSA as a regular purchase, etc.

Make sure that they will return your phone calls promptly.Track all of your income and expenses in report form and review them regularly with a few others you trust and want to see you succeed.  

Just regular mail since you don't have an office is fine.

Most of our house is kept fairly cool but we regularly turn on a gas fireplace to warm up a room we spend most of our time on.

Put in good products and do regular inspections and twice a year HVAC servicing and you will minimize issues.3) This is taken directly from my lease.

It’s been almost a year since you posted this, but I’m wondering if you guys do anything on the regular now?

After THAT, you'll also have a regular inspection contingency in your offer.

Even if your 'self employment income' is small, say you do 5K worth of consulting or contracting 'on the side' to your regular w-2 job.

Another avenue would be to go to those regular rei meetings in your area and see where investors are actively buying....etc....