Giving them right of refusal to match competing offers, renewals for 21 years, and if you break it they are allowed to collect 75% of gross revenues (they only get 50% now)  for the remainder of the lease and that 21 years of renewals. 

Can a tenant living in a property that is for sale make or break a deal for an investor?

It's just details, rules, and numbers that add up to make or break a deal.

Guy 1 is breaking the lease to move across the country.

Cash Flow = income - expenses, and we know you must break down the expenses further, ie. mortgage, insurance, taxes etc.

Seeing what is the lowest occupancy you can have for the deal to break evenCan someone show me what this looks like in practice?

Once you get more experienced, you will learn to break up the home into sections like kitchen, baths, flooring, paint, windows, doors, trims, electrical, plumbing, landscape, roof, HVAC, etc.

Nothing that will break the bank but step above Home Depot / Lowes quality.

But that's TV, and to make (big money like you refer to) in Real Estate it takes specialized knowledge, TIME, and Money as well a the ability to handle Risk without breaking down mentally or emotionally....I'm not saying you can't do it--you certainly can...but it will most likely take time (in addition to your practice) and sometimes stress and TIME combined working at it.How long will it take...unknown.

Own the land, utilities checked out, the permitting is almost done, have a contractor lined up, and about to break ground in 1-2 months.