He has missed our deadlines & missed his own deadlines with all sorts of excuses.

The property I bought was a HUD property so I had a hard deadline to close in 45 days (otherwise I risked paying for each day I went over or possibly loosing the deal).  

Not answering phone or questions, setting almost impossible deadlines for inspections.

Isn't that the purpose of earnest money and a deadline for applying for then securing financing? 

We are past the deadline by a day to do so but seller and seller agent are calm, confident I'm doing the deal.

See if you can get their authorization to go over there (you may not even need it but it's good to call and ask), give the shady characters a firm deadline to get out, and lock down the place with changed locks and an alarm system when the deadline passes.

  : ) @Lance LvovskyMost US tax CPAs/EAs are extremely busy with the 10/15 statutory deadline at this point in time and getting a hold of one for a consult now will be an uphill battle.My advice, read international posts on this forum, jot down the names of CPAs/EAs whose posts you like, and reach out in a few days.

If no lease, have the 30 days in the contract and a large penalty due for missing deadline.

Is there a deadline for the inspection phase? 

Owner occupancy has nothing to do with it, appeal deadline is usually April.