Who was the first Catholic saint? Who was the last Catholic saint? Why were both sainted? What does sainthood confer that being a priest, bishop, cardinal etc. does not?
Can’t really help you, but I would like to observe that being a priest, bishop or cardinal does not require the performance of miracles, whereas sainthood does.
There will be better explanations soon, but originally the Saints were proclaimed as such by almost a popular vote (vox populi) at the local level. Because of this there was not much standardization and little documentation about these early Saints. It wasn’t until 1588 that Pope Sixtus V formalized the process and kept it under the control of the Pope and the Congregation for the Causes of Saints. Finding the first Saint would be hard to judge, then. The latest Saint appears to be Saint Edith Stein on October 11, 1998. As to your last question, a simple difference is that a Saint is dead. The others you mention are meant to guide a Catholic’s daily life, but a Saint is meant to inspire you and to provide intercession for you before God.
sainthood is conferred upon those members of the Communion of Catholicism who we are sure are in heaven. their intercessionary powers are based upon this fact.
now, this is not to say that others are not in heaven. simply that we have no proof.
why those in heaven have greater intercessionary powers than those of us on earth has never been explained to my satisfaction, so I’d say the only difference between a saint and a bishop is a matter of metabolism only.
Not really an answer but the current Pope, John Paul II. Has cannonised, made a saint, more people than any other Pope has.