Well, you could ask your friends just where in the Bible it states that miracles and such powers are pre-requisites for church leaders.
You could also tell them that “infallibility” does not mean, as they too often seem to think, “impeccability” or sinlessness, nor is it a charism of ALL church leaders at all times, but limited solely to the Pope when speaking either ex cathedra on a matter of faith or morals, or to the deposit of teaching of the Magesterium (i.e., the Apostles’ Creed, etc.).
You could also note that miracles still take place today. (Pope JP 2 for example canonized–noted the sainthood–of over 1000 people. Part of the pre-requisite for them to be known as saints was that at least one–in most cases two–known, documented, proven miracles were attributed to them directly).
You could also note that just because something was “written down” in the NT (please remind them that between 33 A.D. and 382 A.D. there was no WRITTEN NT in the form we know it), such as a miracle done by St. Peter, or by St. Paul (and you know there is absolutely nothing that states that say Andrew, James the Lesser, or Jude, among others, performed a “specific miracle”–yet they were certainly “church leaders”) does not mean that such miracles were going to CONTINUE. Readings of the OT note that there were periods where “signs” were widespread, yet FAR MORE PERIODS where there were NO MIRACLES, NO SIGNS, NO PROPHETS, etc. Yet both periods produced good people and good leaders as much as they produced bad people and bad leaders.
I’d just like to see the chapter and verse from Jesus that says, “You can forgive sins, but only so long as you keep up with having people rise from the dead, or multiply those loaves and fishes. Anybody in later years who comes along and claims to forgive sins based simply on being ordained by someone who was ordained by someone who was ordained. . .yadda back to one of my apostles, who abides by My Creed, seeks to do My Commandments, eats My Flesh and drinks My Blood, but DOESN’T DO A MIRACLE. . .well, don’t bother. If he doesn’t slay 'em in the spirit or do miraculous healing, he isn’t a REAL PRIEST.”
I haven’t found that verse in my Bible yet. . .so perhaps your friends could oblige?