In Texas the statute of limitation expires after the maximum amount of time allowed has run.

My realtor states since my last extension expired, technically I'm not in contract anymore, and would like me to sign to the cancellation.I don't want to sign the cancellation.   

The two extra months would just be a safety time period to make sure that I get the cash of re-fi before the short term note expires.

Should the tenant not vacate after the lease has expired - this is important:  Do NOT accept any rent from the tenant. 

I will add:-See 100 houses for listed sale, track them, walk through them, put info on index cards, list price, sold price, DOM (days on the market), expired listing, agent's name?

The agency would hold it in escrow until the purchase offer expired or the sale completed.

I was planning on just keeping them as is until the lease expired but they are alot of work and would rather just raise rents now. 

If not under rent control, you still need to follow your lease and keep the current rate until it expires.- If you have a month-to-month rental agreement, you still have to give notice- 30 days if the increase is 10% or less- 60 days if the increase is higher than 10%

I let them know 28 days before the lease expire and offered; after the lease agreement is done I offered them and extra month stay.

If not, you can't raise their rents, without their permission, until the current lease expires.