I do a fair number of construction loans- more lately than before, that’s for sure, but enough to have seen a lot of bids from a lot of builders. I have had many people come to me wanting to do what you describe and have become somewhat of a dream crusher on the topic, so my apologies in advance but hopefully this is all useful info:

The first problem with building a small/tiny house is that some costs do not scale at all with size of house- the septic system for a 500 square foot house is not 1/10 the cost of the system for a 5000 square foot house, getting utilities to the site is the same no matter what, the well is likely the same (or if you are talking city utilities, the cost to hook up to sewer and water is the same for any hookup) and then tradespeople will all have a kind of minimum “make it worth my time to drive there” figure, so you’ll find the roof and framing etc won’t scale directly to house size either. I have not seen someone end up building anything that didn’t roll in on wheels for less than 285k.

250 you might be right there, if you can find a lot that both allows two buildings of that size and has access to public utilities, but keep in mind that you won’t be able to get a mortgage on such a project since mortgages require appraisals that show sold prices of comparable properties, which you probably won’t have. You also will have your resale value limited by the fact that future buyers will also have to pay cash, which knocks out a big part of your already kind of limited buyer pool.

I think something like this is mostly a passion project and something you do if it’s your dream and money isn’t an object- if you’re just trying to keep a 250k budget and want somewhere charming with some privacy, and don’t mind not having a ton in the way of creature comforts, I think if you keep an eye out you can find something that you would be able to get a loan on (or have resale prospects to people who need a loan) with some land in Varina