How to get owner occupant loan if target is already leased?

[Colin Simon]

I live in a (relatively)expensive area, so coming in with 5% down and a little PMI is reasonable for me, but 20% down or more would just be a waiting game. Once I'm in I would house hack and make it work.

There are a lot of options with withdrawn properties that have been put back up for rent. This seems like an ideal way to find targets for off-market deals... you already know they want to sell. I could approach the seller after "holdover" with an offer ~5% less than list and it'd still net them the same as their list price(which they didn't even get, so perhaps lowball a little more).

But, since they've been rented again through July 31, how do I satisfy the owner-occupancy requirements? 

1. Go under contract, then negotiate an option contract with the tenants; if I close on the house, I get to give them a free month and then their lease ends.
2. Same, but try to directly buy them out?
3. Also same, but you offer $100, $200, $500 upfront just to sign the option, so if the house doesn't close they still make a quick buck?

What are the time limits with beginning the owner occupant loan? E.g. if I close July 25 and the tenants' lease ends July 31, then I could move in, and it seems to me like my intent lines up with my stated direction.