Sorry, I missed this question until now:
And the second question is the same date as Apollo 16 returned just two days later (April 27), but that is impossible, the return can not take less than three days.
You're looking at the calendar date, based on Greenwich Mean Time (GMT or UTC).
Houston time (or Buenos Aires time) Apollo 16 departed lunar orbit on April 24 at 20:18 Central Standard Time for Houston (23:18 Buenos Aires time) and splashed down on April 27 at 13:45 CST (16:45 BA). April 24 to April 27 is three calender days.
The actual flight time from TEI to splashdown for Apollo 16 was 65 hours 27 minutes (all but one of the lunar returns took less than 72 hours, with variations based on the actual distance from the Moon to Earth and the desired splashdown location and time-of-day at that location). During that time, the astronauts had 3 sleep periods of 7.5 to 8.75 hours; so as far as the astronauts, the mission controllers and everyone else in most of the Western Hemisphere were concerned, it was three days.