So here’s what I figure about the relationships between the Johnsons and the Dingleys (There’s probably more):
Lucy DINGLEY (1780 - 1857), parents William DINGLEY & Nancy PRIEST, married Aaron JOHNSON (1797).
Ira (1789 - 1864) parents, William DINGLEY & Nancy PRIEST, m. Elizabeth UNKNOWN.
Edward DINGLEY (1831 - 1900), parents Ira DINGLEY & Elizabeth UNKNOWN, married Matilda JOHNSON
Lucy and Ira (1789) , Edward’s grandfather, are siblings. Therefore, Lucy is Edward’s great-aunt.
Aaron JOHNSON & Lucy DINGLEY are Matilda’s grandparents.
So Edward and Matilda are 1st cousins once removed.