Questions regarding selling raw land with owner financing

[Nickolaus Banks]

I signed a purchase agreement through a broker to buy 15 acres. The land is 15 minutes from Bixby, Oklahoma. From what I understand the property is going through the probate process. I signed the contract January 1, paid my earnest money, and closing was projected for March 1. It is now April 1, and the seller wants to extend closing. My intent with this property, is to sell with owner financing(54,000 at 7% for 5-10 year term/6,000 down). I bought with private money(47,500 at 6% for 5 year term).  Below are some main question that I have regarding this situation.

1. If the seller does not close on projected date can I get out of contract and receive my earnest money back?
2. If the seller wants to extend the closing, can we modify the contract and, for example," for every day that closing is extended, there will be 100 dollars deducted from original purchase price"
3. Can I start marketing the property, before I close on it? Once I do find a buyer, can I have the buyer sign a purchase agreement before I close on the property?
4. What is the correct way to sell with owner financing? What needs to happen to deed and title? Correct contracts?

Any advice would be greatly appreciated?

Thanks,

Nick