First of al, not all Protestants would say that all agree on the essentials. Secondly, even those that do, if pressed a bit, would probaby say it is possible for people to stray so far that they simply move outside of the Church. They might say, for example, that JWs are in that position. Those people would not be included in the idea that all Christians are protected on the essentials. Thirdly, as far as the people who might say that there is protection on the essentials, I don't think any would consider even one of the items on the OP list as essential. They might say they are important questions, but not essential. What would be essential, in the view of such people, would be faith in Christ, or maybe even hope that they can be/are saved by God, or willingness to accept God's love when they see it being offered. That leaves a pretty wide field I would say. Fourthly - I have no doubt that there are people out there that could be tied in knots with this question, that cannot think clearly about the implications of their theology, or get confused about theological ideas. That is because they are not people who are good at thinking, or they haven't had the opportunity to learn or learn good theology. That is ok, those people exist in every group, and we shouldn't use their confusion as a straw man, or to beat them up with. Not only because it would be uncharitable, but if we rounded up those people from every religious group, we would all look like our theology was totally incoherent, no matter what group we belong to.