Unbeaten middleweight Agyarko, 28, will face 30-year-old Englishman Ishmael Davis, while 35-year-old McKenna will take on fellow Irishman Dylan Moran.
McKenna stopped Moran in the second round of their welterweight contest in Waterford last December.
Matchroom have also confirmed Patrick Brown, who represented Great Britain at the 2024 Olympics, and Commonwealth Games bronze medallist Aaron Bowen will appear on the bill, with more fights still to be added.
Earlier this week, Windsor Park was confirmed as the venue for Donovan and Crocker’s contest for the vacant IBF welterweight belt.
The stadium last hosted a boxing event in August 2018 when two-weight world champion Carl Frampton defeated Australian Luke Jackson.
Donovan and Crocker’s rematch will be the first world title bout between two fighters from Ireland.
Their first meeting on 1 March was a final eliminator for the IBF title and ended in controversial fashion with Crocker taking the win by disqualification in front of a 8,500 crowd at the SSE Arena in his native Belfast.