Cannonization is a laborious process, and I expect that all possible objections and rejected them. Saints are not required to be perfect, in fact none were, only Christ was perfect. Popes are not infallible in their judgements, only in a few, very rare, declarations on dogma or morality.
Not according to the The Catholic Anti-Defamation League. According to the article the canonisation was "infallible".
True, the process of cannonization is truly laborious. Even those persons that are on the “fasttrack” Blessed Mother Teresa of Calcutta and even John Paul II, who are the most well-known examples, the process has been speeded up, but by the little bit. But it is still a bit laborious.