Simple Past or Present Perfect?

Britney Spears (be) keen on singing ever since she (be) a little girl.
Since she (release) her first album 'Baby one more time', she (sell) millions of CDs.
She (experience) personal struggles since she (get) divorced in 2007.
Yet, music critics (consider) her as one of the most famous female vocalists of the 21st century.
They (compare) her to her pop rival, Christina Aguilera.
Britney (name) Michael Jackson as a source of inspiration and was said to be devasted when he (die) .