Belford, 22, has joined on a season-long loan from Swindon, with no recall clause included in the deal.
"I've followed his career since he was at Liverpool and watched his progress at Swindon," said boss Andy Bishop.
Former Manchester United trainee Cofie, 25, joins from AFC Telford and has also played for Wrexham and Crawley.
The Sandgrounders have also announced that striker Connor McCarthy has signed a new one-year deal.
Find all the latest football transfers on our dedicated page.
National League side Southport have signed goalkeeper Tyrell Belford on loan and brought in striker John Cofie on a free transfer.