But does anyone know if an owner can collect from a co-signer (non-tenant) who is not in financial distress?

This may result in me getting a co-signer which is fine or having to go with maybe a hard money loan which I don’t want to do.

Me and my realtor don't think the seller will wait for me to add a co-signer (my wife) or even start a new job.This house hack is perfect for me and my family, numbers are good, space and area is good. 

You need 3 active credit lines, or you’ll need a co-signer.

Sure, it's called a co-signer. 

There is a co-applicant who seems with good credit and financials.Have you ever come across situation like this?

The listing agent will get what was offered as a co-broker commission as their marketing brought the buyer and the buyer did not have an agent.

I am looking to buy a property with a co-borrower and the main lender that we are working with is only counting my co-borrower's income and not mine for a reason that I don't see valid. 

Depending on what types of student loans you need, whether you have a co-signer, and how much you’ve already borrowed, I just wouldn’t want additional debt outside of school to potentially result in you not getting approved for student loans needed to finish your education (if that’s your goal anyway).

Or you can find a co-borrower.