John-Paul II chose his immediate predecessor’s name, and he had combined those of his two most recent predecessors.
The three most recent popes are the longest run of Popes with none choosing the name (counting JPI as choosing both of two recent predecessos) of a recent (one, two, or three back) predecessor since the 1500s.
Yes, it of course happens, but when it does it is usually a signal that the new pope intends to continue with the vision of his predecessor.
(John Paul II is also something of an anomaly, because John Paul I died barely a month into his papacy and so didn't have time to put in place any real agenda. John Paul II was more commemorating John Paul I the man.)
Yes, but the past half century has been a rather unusual time for the Church since it's coming out of one of the more consequential ecumenical councils. It typically takes the Church a few generations to come to an agreement about the meaning of an important council. But in the immediate wake of it there's usually a wider diversity of visions.
The three most recent popes are the longest run of Popes with none choosing the name (counting JPI as choosing both of two recent predecessos) of a recent (one, two, or three back) predecessor since the 1500s.