Leo says he knew Piper was sick and he could only hear Prue and Phoebe calling him because he was staying nearby. The rest of the series establishes that Leo can hear his charges calling no matter how far away he is.
When Piper is cleaning the club after being awakened, she keeps cleaning the same areas. She cleans a few tables, wipes down the bar, takes glasses off the bar, goes to clean the same tables as before. The next time the bar is shown, the glasses have reappeared. She wipes down the bar again, moves the glasses again, and starts over at the tables. This happens at least five times before Phoebe stops her for moving at an extra fast speed.
When astral Prue is looking at the book of shadows for the reversal spell, it shows two verses. "What was awakened from its sleep, Must once again slumber deep.
Return the disease to whence it came. So life can ease back to the same." When she returns to the hospital room she only tells Piper and Phoebe the first verse, and she and Phoebe say it twice before Piper collapses.
Piper's spirit leaves her body and starts to move on by itself. In other episodes, it is shown that the Angel of Death comes to wherever a person dies and leads them to the next life.
When Dr. Williamson is using the defibrillator on Piper he would have had to take her watch and bracelets off Or the metals in them would have burned Pipers wrists.
Kiwano is grown in the United States. In fact it is even grown in California where "Charmed" is set. There would be no need for P3's bartender to smuggle the fruit in from South America.
The doctor called Piper's death without going through the medical procedure of determining brain death, a determination that has never been documented to have been reversed.