While I agree that other types of fish and vegetables would be a great idea, lettuce would make a terrible consumable. As far as realism goes, it's basically just water and roughage, so it wouldn't make sense for a person stranded on a raft to spend energy growing something like that.
Doors and thatch roofing would be a fun addition to the building aspect of this game. The idea for larger chests and steel-reinforced foundation would be awesome to see too.