Except, of course, that Biblical interpretations will be varied among those “nondenominational”. That means they really cannot be lumped into a denomination having a specific dogma.
Essential to being a Christian, and at our church to be a pastor or member are five things:
Belief in God as the Trinity
Deity of Christ
Salvation by Grace Alone
Inerrancy and authority of Scripture
Return of Christ to rule, reign and Judge
He talked about three other rankings as well. The next group is where denominations may differ but they may still be Christians. Things like baptism (adult vs. children). I need to listen to the sermon again - but I'm guessing that gay marriage might be in this group, but then that would go against the authority of Scripture in the first group.
Third group we shouldn't divide over but it is important to inform ones own faith - things like old/young earth creation, end times positions, etc.
Fourth group is trivial - did Adam have a belly button?