Is the Pope considered infallible when determining who is and who isn't a Saint?
What I found most appalling is the Pope's desire to make the "father" of the European Union a saint. Even the most ignorant observer can realize that the EU is at odds with everything Christian.
Only as definitively stated by The Vatican Council - and I don't mean Vat II. He must speak to the whole world, on matters of dogma, concerning faith and morals, saying that this is imminent in Revelation and irreformable. Some suggest a lesser but still serious standard applies to the pronouncements on a possible female priesthood. But that isn't technically an exercise of the Solemn Magisterium.
The irony is that in the defense of this Pope's foolishness in many things, generally stemming from ecumenism, his defenders tend to say that everything he does is infallible, but that rarely were any Popes prior to Paul VI infallible in the same way. Those who criticize His Holiness do so on the basis of all those other Popes, Tradition, and that once the Truth is served, those interested in Truth wish it applied and spread to the whole world, not 'reformed' and remade.
Absolutely not. The declaration of someone as a saint is not a matter of doctrine.
As far as I know, there have been two proclamations by the Pope, the Immaculate Conception and the Assumption, which have been considered doctrine due to the unique infallibility of the Pope. Although I would also say, it appears to me that the Pope is infallible in his assertion that abortion is always a moral evil and must be opposed by Christians. He seems to be purposely presenting the conditions of infallibility when he addressed the bubject in an encyclical to the world.