There's a lot of legal and compliance activity that would need to be outsourced. The technology could be mostly outsourced. In theory your trading strategy can be automated, and while it works, could be largely hands-off.
I think you can probably pass all the compliance checks with a single person supported by outsourced contractors, so long as you have the right licenses.
So the single person would need to supervise all the outsourced activity, review and sign all the docs, monitor the strategy, and do the sales and marketing.
While it's theoretically possible, it'd probably make more sense to have at least two people.
Trading on a brokerage account is one thing. Selling the fund to investors is another thing. If you are running an overgrown family office and you have a few outside investors that are an easy sell you might not have to work that hard at marketing, but if you want to get a substantial A.U.M. from many investors, then selling the fund is a full time job I think.