There are likely similar other calculators available online. 

I have a name and his last name is unique, but in my personal search for him online hasn't yielded much.

If so, would you have any suggestion of the online courses to prepare for TX Realtor License? 

I will follow up with the city hall tomorrow and will keep searching online, just thought I'd ask BP too.

Don't rely on lines of credit either (HELOC, CC, etc).

You can contact most major retailers online, Starbucks used to have a specific email,

I am involved in a few Facebook groups and other online groups, but I have never had the same level of experience as an in person group.

If all fails, please consider reaching out to those representing the seller online and see what company/individual is currently managing the units prior to the sales transaction.... this could give you some great insight. 

From what I can find online, whether or not the lender will allow us to count future rent from the other units toward the loan amount depends on the specific lender.Question: anyone have advice on getting pre-approved with a lender that will be more likely consider future rent payments toward the loan amount (ie the loan amount will be greater than just our w2 jobs would provide)?

You can consider money market funds or online banks like ally bank where they currently have a 0.50% APY for their savings account.