Regarding uncovered cut fruit in the fruit juice that was left uncovered overnight, may it be eaten or should it be discarded?
You may eat it and it should not be discarded. The issue with foods that were left uncovered overnight only applies to eggs onions and garlics, and even then, only if they were fully peeled. It does not apply to fruits.
Regarding the liquid that was left open, we are not makpid on giluy nowadays, especially in the United States where snakes are not common.
Nidda 17a, Y:D 116-1.