Strategy
Manami wants to be as agile and difficult to catch as she possibly can, for two reasons: the first is that the range on her normals is catastrophically short, so there's not much point to standing around trying to play footsies. The second is that if she gets caught by the opponent, her low defense value means a single mistake can be fatal.
Neutral
Manami wants to spend most of her time harassing people in neutral with a combination of Goro Goro Attack and Banzai Attack to mess with the opponent's timing, as well as j.LK > j.HK chains for both approach and runaway.
Offense
If she's able to establish offense up close, you mostly want to prioritise her highly rewarding normal throw and command throw.
Defense
If Manami finds herself on the defense, she has to rely mostly on chicken blocking and guard cancels, since she has literally nothing else to help with her defense.
Matchups
To come.