I will be the first to say that it is very hard to cover all Protestant beliefs about any doctrine. There are just so many of them. But Kreeft does get it right for many Protestant denominations.
This is a brief story of his faith upbringing and conversion
http://www.peterkreeft.com/topics/hauled-aboard.htm
Certainly. There are, for example, 3 distinct views of Communion/Lord's Supper. But it doesn't show good scholarship to make broad generalizations and try to fit all protestants into it.