Heresies always come in multiples, and they are inter-related. By contrast, there is only one Truth just as there is only one true God. Paganism and heresy have the character of many, but God's truth has the character of one.
I have noticed recently that here are many and varying forms of Arminianism. In one way or another, they all rely upon elevating the authority of man and diminishing the authority of God. These characteristics they also share with Pelagianism and Arianism which are perhaps the two greatest heresies of the early Church.
Meanwhile, there has always been but one Reformed view (minor quibbles notwithstanding). Reformed doctrine is related to nothing else except that it's chief objective is exactly like that of all the church fathers in the first 4 centuries... to elevate the authority of God and to diminish the authority of man.
Ecumenicalism is multiple doctrines in co-habitation. Therefore, it should not be surprising to find heresy wherever you find ecumenicalism, simply because it has the character of 'many' as opposed to 'one'.
