Dig and remove around 200 square feet of an old concrete driveway, frame and lay down the concrete (concrete will be ordered from concrete supply business) and complete a brick ribbon around the driveway.

I would split the utilities based on square footage of each unit, then add it to the tenant's bill.

But it also had a small 200 square foot guest house in the back which we rented out for $1500.

I'd assume CA and WA would be similar.  

I have considered adding an ADU in the back, but since I am limited to 75% of the main house square footage, this is also probably not worth it.     

how much is the land and exit prices per square foot?

Building a 4,000-square-foot, three-story duplex with a 1,000-square-foot ADU could cost about $1.83 million, including construction and permits (excluding land).

I gave my Optionees a square deal. it's not a bad thing to know how to properly execute lease options but I wouldn't pay money to learn it or think I was going to build wealth with it. 

LOL.The biggest bankruptcy in Washington State history was Michael Mastro, a real estate investor who according to court documents with debts to investors of $547,000,000.

The property is 2 stories and 1,875 square feet and was constructed in 2024.