How far are you going to take that? I expect that you'll find, eventually, that you'll have to draw a line somewhere.
If Federal Visionists, because of their positions on social issues, are fine, then what about conservative Roman Catholics? JWs? Mormons? Muslims? We might share quite a few of the same positions with these. On the surface, at least. The foundations are very different however. A Christian is not merely a moralist; his morality is grounded in the Word. I think it quite obvious that he should think twice about partnering with anyone whose doctrine proves him an enemy of the gospel.