The duo arrive at the Lane from Yaxley, having left Cambridge United at the end of the previous season.
While at the Abbey Stadium, both players progressed through the youth academy, with goalkeeper Iron making one first team appearance in a 4-0 home win against Southampton Under-23s in the EFL Trophy in October 2018.
Iron also had loan spells with St Neots Town, St Ives Town and Ely City, with attacker Bennett also appearing for St Neots and Mildenhall Town.
Also re-signing with the club ahead of the Pitching In Northern Premier League 2021/22 season are Jon Kaye, who has been confirmed as the new club captain following the departure of Josh Pope, alongside Joe Carden, Alfie Connor, Ali Conway, and Josh James.
Soham Town Rangers will compete in Northern Premier League Midlands in 2021/22.