If all else fails, once you are the owner, just have a locksmith come out and let you in. 

If the tenant that resides there still gives you a hard time, have a locksmith handy along with the police. 

There a locksmiths that will inspect your property and complete the required rekey for you.

Ask them how many contacts they have of handymen, cleaners, locksmiths.

He tells me, locksmiths gets paid, plumbers get paid so why shouldn't he?

HI,I have a tenant that on last renewal notice they signed that they won't be renewing the lease, in fact they already moved but still have some stuff to take out, I did give them the extra few days, now I was going to pick up the keys as they were supposed to finish up taking out everything, and they just told me that they had an emergency and could not come today. can I legally call my locksmith to open the lock and change it while they still have their stuff?

I'm pretty sure the cops won't come for something like that here.Call a locksmith if you don't have a key.

A locksmith tipped me on that one years ago, get rid of the locking doorknobs so they have to have a key to lock up on their way out.

Cleveland is pretty similar.The process is as follows.On move out day you go to the house with the Bailiffs, Court approved movers & your locksmith. 

I think its angry boyfriends :)Regarding your list... a locksmith told me years ago and I've been using this ever since with 100% success.