A LEASE/OPTION is very dangerous:
There is no set CONTRACT,
The TERMS can be daunting,
No one can see into the future; how much the house should sell for in 3-5 years, so it will have to be inflated to protect the Seller,
You don't know where you will be, financially, in 3-5 years,
You would lose all the money you have put in to the Option,
IT WILL NOT HELP YOU RE-BUILD YOUR CREDIT!
Renting and paying your bill will re-build your credit.