There is no physical Body of Christ; no religion that is the Body of Christ...
There are likely Christians in each of the groups you mention...And not everyone who is a member of your physical orthodox (to some) religions are going to heaven...
The problem with a simple statement of: you must believe in order to be saved, is that what does that belief consist of? The whole history of the Church is trying to define what that belief should be.
The Oneness Pentecostals, for instance, believe in only One God and that Father, Son and Holy Spirit are one person all combined. Does that remove them from consideration for salvation? If not, then where is the line?
Catholicism attempts to define such things and calls them doctrine. How loose can one be? Can one be Wiccan and be saved? Can one be Jehovah's Witness and be saved? If so, why?
Maybe your church can't figure it out but other churches certainly have...
The Oneness Pentecostals, for instance, believe in only One God and that Father, Son and Holy Spirit are one person all combined. Does that remove them from consideration for salvation? If not, then where is the line?
Catholicism attempts to define such things and calls them doctrine. How loose can one be? Can one be Wiccan and be saved? Can one be Jehovah's Witness and be saved? If so, why?
The Catholic religion is a religion of legalisms...You must do this and you must do that...You must hold the cup the right way...If you do things just right, you MAY receive salvation after you die...
There's not too many things required to become a Christian...
One is to realize that you are lost and are in need of a Savior, and there's nothing you can do to save yourself...IF you don't know you need a Savior, there's nothing to be saved from, or to...
Of course God can save a Wiccan, a Jehova's Witness and a Muzlim...It's a little tougher, but God can even save a Catholic...
The real question is: how does one remain in the same religion AFTER being saved...And there are a number of reasons why some people do...
Some have been in the same religion for so long, they don't know how to leave...Some have friends and family they don't want to leave...They were baptized in that church, etc...
But many, or most do leave their non Christian religions...