So his statements in support of Islam and against Catholic teachings are not official teachings of the Pope?
There are gradations of teachings, but anything of any seriousness will be published as a document in a journal called the Acta Apostolic Sedes (abbreviated AAS), and formally addressed to those who need to actually read it.
Spouting off to the New York Times is great fun, no doubt, but it is a private hobby.
The teachings of one Pope also need to be read in light of the teachings of other Popes. With this one, unless it either appears in the AAS or pertains directly to something I am doing or teaching about, I generally simply go with what other Popes have said, in light of a principal outlined by Pius XII in an encyclical addressed to everyone and published in the AAS which runs to the effect: interpret the less clear in light of the more clear, and not the more clear in the light of the less clear, no matter which one was published first. (I believe this is fro Humani Generis, published in 1950, but it may be from Divino Afflante Spiritu, published in 1943).
“So his statements in support of Islam and against Catholic teachings are not official teachings of the Pope?”
Right. he would cease to be Pope; Pope in name only.