Striker Isaac Olaofe, 20, spent time on loan at Sutton United last season while full-back Danny McNamara, 21, had a loan spell at Newport County.
Davidson, who worked with both players during his time at Millwall, told the club website: "Danny's an out-and-out defender but has quality further up the field as well. Isaac can play right across the frontline and gives us fluidity in that area of the pitch."