For instance, you have the 70% rule for rehab and fix then you have the 2% rule and then 50% for buy and hold these are some guides on how to determine if a property is worth buying.  

Is their a rule of thumb for this sort of thing, percentage wise?

The exempted properties are up to 2 years with an additional 25% interest after the first year making the interest rate 50%. 

Also some new landlord rules up in Seattle are making it an unattractive market.  

Offer 50% of their current deposit for the keys and get a written Release of Lease, date, amount in trade for $xxx at surrender of the keys.  

Here in KC, Peak Financial will do that (but only at 50% LTV, I believe).

You should be able to secure a 50% LTV mortgage with no problem with really pretty minimal income showing I would think.

It is the fine details that are often different (eg, there is no such thing as a forclosure in Ontario, there is no "courthouse steps" auction, there is no "absentee owner list" and the rules regarding landlord/tenant are wildly anti-landlord here).

If it's more than a week, I won't use this method, and I will gladly pay the $50 for the week of borrowed power. 

Hello EveryoneI'm Real ABR, GRI Estate Agent in San Antonio Texas, I mentor new real estate agents and investors to train them the whole prosses and TREC rules.