no, there isn't

Of course it's exclusionary; it's a definition!

One cannot claim the name Christian while denying the basic facts about the Christ Himself. The others you mentioned all deny the real historical Jesus in some way, so I would not call them Christians at all.

The fact is that Jesus is God in the flesh, who died for the sins of the whole world. He was raised from the dead and seen by many witnesses. Investigators, many of whom were hostile to the Bible, were convinced by the evidence that this resurrection did actually take place exactly as the Bible says.

The books of the Bible that we have today are established as having been accepted by the first century believers almost immediately, and well before there ever was a "Rome" (i.e. RCC) to 'sanction' them. Please refer to the many posts that have documented these things already, or feel free to check the resources at my web.

John is noted by many commentators as directing much of his writings AGAINST Gnosticism so please don't try to pass it off as a 'christian' sect.