Would such a portfolio be valued using individual appraisals or NOI and cap rate? 

Using this information I will be contacting individuals with liens on their home that are NOT foreclosed yet, but instead using the foreclosure as leverage to buy the land cheap (5-10% of market value) from an individual.

Higher end rent would require some repairs and rehab.Capex $285Maintenance $285Vacancy $190Insurance $110Water & Sewer $85Taxes $1042 ($12,500 per year).Structure of the property is in decent condition, no current leaks or issues found.Two leases are month to month as of this month, the one bedroom has a lease until august.Gas, heat, and electricity are all paid by the tenants individually.

Once I feel I have an appropriate rent price, I require all of my prospective tenants to complete an application through an online credit check & tenant application website.  

Well said, @Vince DeCrow.Reminds me back in the day when I was invested 100% in all "High~Tech" Individual stocks.

They help you understand what all the numbers are for your individual cases?

If they have an online archive you may be able to search the address there.

They have a positive online reputation.

I am a landlord with a unique SFH rental in the SF bay area, I lease out (month to month) individual bedrooms and manage the property off site (I don't live there).

Usually when someone is interested enough to send me a message, I respond with  a link to my online application and request they fill it out.