Deacon's Alive??? is Sarah's lab note 1 of 6, a short audio log she records on Wizard Island. You get it automatically during the story mission A War We Can Win, so it can't be missed.
Sarah is stunned to find Deacon alive among Captain Kouri's new recruits. NERO had told her the camp where he waited was overrun with no survivors.
It gives Sarah's side of the reunion and why she believed Deacon was dead.
Riding With Deacon
Riding With Deacon is Sarah's lab note 4 of 6, a short audio log she records on Wizard Island. You get it automatically during the story mission Just Another Acquisition Form, so it can't be missed.
Sarah's Lab Notes
Sarah's Lab Notes are six personal research notes written by Sarah Whitaker. They are rewards for main story missions in Crater Lake, so you get them just by playing on.
Silicate
Silicate is Sarah's lab note 3 of 6, a short audio log she records on Wizard Island. You get it automatically during the story mission Afraid Of A Little Competition?, so it can't be missed.
Teensy Tabby
Teensy Tabby is Sarah's lab note 6 of 6, a short audio log she records on Wizard Island. You get it automatically during the story mission This Could Be It, so it can't be missed.