Two individuals can simultaneously be "chief administrator" with one being of a department and the other of the entire hospital. They can also change roles.
Othigo was on the way out in early 2009 because in late 2008, these same newspapers reported that under her administration, however broad that was, patients reported that doctors at CPGH were demanding bribes in exchange for treatment.
Transitions can be messy and newspaper reporting sloppy, so public emergence of Maganga as chief of the hospital (with both phonetic spellings of his African name) could have easily been delayed by a few months, say from January to April.
You have reasonable suspicions about conflicting details, but you persist in falsely claiming that your personal suspicions regarding newspaper discrepancies that go both ways "prove" something. Your suspicions about mere discrepancies for which there are alternate exculpatory explanations prove nothing, in my opinion.