That's it right there. Since he wants to keep ownership of the land like the government does. He can build stuff like condo buildings. Yet those costs are only in the ~50 million range for a big one. You obviously sell the units and have your government be the condo board. Basically recouping any costs here. There you have housing.
Next is food. Are they producing food? Maybe not necessary, truck it in via walmart.
Next you want walmart warehouses for food and goods. That builds itself, walmart is the one who takes on the cost because they'll pay that off in the long run.
Utilities are built in, bringing big power to the edge of your city will be costly, but we're talking less than 50 million. Anything more than that and you start looking at doing it yourself.
security and safety doesnt have a problem yet because you don't have that part of society. Stuff like police are paid for and expand with the population.
Next you need entertainment and similar. There's a big chunk of $. Probably going to be $5 billion and not pay for itself for a long time, but it will.
What more do you need? Small time stuff? Not going to really break the bank.