The Shakers handed caretaker boss Ronnie Jepson a deal until January on Friday but they looked to be heading for defeat after Anthony Stewart's 16th-minute goal.
However, Tom Soares' 69th-minute effort and Edjenguele's winner two minutes from time secured Jepson his first win since replacing Kevin Blackwell earlier in October, while Matt Bloomfield received his marching orders for the hosts.
Stewart gave Wycombe the lead from a corner, meeting Josh Scowen's cross at the far post to volley into the top corner.
Kortney Hause had a shot cleared off the line for the Chairboys after the break, but Soares grabbed a deserved equaliser for the visitors when he finished Anton Forrester's clever cut-back.
The home side were then reduced to 10 men on 76 minutes when Bloomfield was sent off for a rash challenge on Shaun Beeley and Edjenguele climbed highest to head home Chris Sedgwick's corner to seal a surprise win.