Factually most of the signers were Anglicans.
Live your fantasy.
By which you mean Episcopalian.
Factually, the Episcopalians of the time affirmed an EXPLICITLY Calvinistic Creed in their Thirty-Nine Articles.
To be a confessing Episcopalian, in good membership standing, at the time, meant being a Calvinist in terms of Predestinarian beliefs. By express creedal confession.