grammatical number - Does "two patients' excised livers" sound like that each of them has more than one liver?

Which of the following is correct/preferable?

1. Two patients’ excised liver showed no histological evidence of HCC.


2. Two patients’ excised livers showed no histological evidence of HCC.

Similarly, "they live their happy life" or "they live their happy lives", "they lead a happy life" or "they lead happy lives".

There are lots and lots of this kind of problems in English!