The trio will be part of the Rose squad trying to earn a shot a promotion to the Scottish Lowland Football League by attempting to win the 2022-23 East of Scotland Premier Division.
“I’m absolutely delighted,” Herd, who took over from Brown Ferguson as Rose gaffer last August, told the Journal and Gazette. “They’ve been brilliant since we came in.
"Obviously we signed McMullan and McKenzie from Bo’ness and they’ve been great additions.
"And we were really fortunate that Cammy was part of the squad when we came in. So it’s brilliant that he’s signed up as well.
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"Everybody in the squad is signed for the next two seasons. We are all in this together, to try and get to the Lowland League.
"That’s got to be the main objective.”
A summer signing spree has seen Herd add ex-Newtongrange Star centre half/full back Alex Webb, former Albion Rovers goalkeeper Cameron Binnie, ex-Bo’ness United centre back Greg Skinner and former Stirling University midfielder Ben Davidson.
Also in are young keeper Matthew Wallace, former Clyde forward Owen Andrew and ex-Lothian Thistle Hutchison Vale midfielder Sandy Cunningham.
"Transfer business is closed this summer unless anything extraordinary happens,” Herd – who now has a squad of 20 players – added.
"We’re happy with the squad so we’re not trying to make any more additions.
"That’s us just trying to get it all settled, get a look at everybody in the pre-season games and get the preferred squad and starting 11 we’re going to be looking for and then we go from there.”