Last minute advice - extending my tenants' lease purchase contract today.

I'm really torn on this decision especially with my wife's advice to me.

My tenants are great. Never missed a payment. Keep the house clean. Promptly let me know about maintenance. The yard looks pretty good. Garden is actually tended to.

Last January (2016) I let them know that I wanted to sell the house, and they expressed interest in buying it. They had major credit issues when they first started renting in 2014 but told me they were working to restore their credit.

We switched to a lease purchase contract in February 2016 and they provided written notices from a loan adviser that they could close on the house by November 17, 2016. I decided to give them a little leeway in the contract and set the end of the lease purchase date to January 31, 2017 in case inspections/paperwork/scheduling caused a delay.

They informed me a few weeks ago that they couldn't go through with the sale because of one credit judgment on his credit report. He said the loan adviser told him it shouldn't have been a problem because it was from a decade ago. He switched to a new mortgage company and told me he's working hard to get the credit judgment removed.

I asked him for a definitive timeline and he couldn't give me one. Said hopefully March maybe April.

He and his wife both work. I know his credit score was 450 when they moved in. She had a score of 0. That was 2.5 years ago.

My wife said I should give them until March 31st and no longer. There's a good chance we will be moving out of state in August, so she wants us to have a full four months to sell the house.

Here's the dilemma in the numbers:

My mortgage payment increased this year to $1288 after I lost homestead exemption and after a shortage in my escrow.

My tenants pay $1250/month for rent and a $100/month rent premium.

They paid $3000 at the start of the lease purchase, which I can keep if they don't sell the house plus $1200 in rent premium payments.

I'm losing $33 each month starting in February and I have $1200 in savings to cover any maintenance issues.

If I kick them out in March, I'll have a total of $6360 to cover four mortgage payments before I move ($5152) with a remaining $1208 for any repairs/fixing up for selling the house.

If my tenants do buy the house, I'll make $14k on the sale before capital gains taxes. No realtor fees involved.

If my tenants don't buy the house, I don't think I could sell the house for as much as they're going to pay. Maybe a few thousand less (houses in the area are selling for around $169k, and they're going to pay $172,999).

If I have to use realtors, I'll lose more than half the equity if I sell for $172,999.

I'm just starting to feel burned by both scenarios. We also really want out of this house. It's been a goddamn burden for five years now, and I blame it for ruining a chance for me to go to graduate school (spent $10k on maintenance last year which put us in the red right as we moved to a new state for my school).

TL;DR - Tenants and I are going to sign an extension to their lease purchase contract, which they couldn't complete due to a credit judgment. Wife says give them two months at the most but I think we should give them longer because we'll make more money if they do buy the house. We're losing money each month now in rent, but I'm not sure we can even sell the house for a decent amount if we put it on the market right now.