Without an agent, the seller is also handling everything the lawyer does not, such as pricing, marketing, showings and negotiating the offer, which makes the lawyer's role more important, not less, since it is the only professional check on the paperwork before money and title change hands.
Budget the same $800 to $1,500 in legal fees a represented sale would carry, since the closing work is identical either way; the only real savings from FSBO comes from not paying an agent's commission, not from skipping the lawyer.
A private valuation before setting a list price protects a FSBO seller from the pricing mistakes an agent would normally catch. Get your hand-reviewed valuation from Joel Dyck.