Since Natsumi can only heal people with her passive if she lands on their panel, Natsumi is forced to be aggressive to make as much use out of her passive as possible.
Since the cost of being KO'd is minimal during normas 1 and 2, this is where Natsumi should fight anyone if she is reasonably healthy since her potential star gen is unparalleled that early in the game.
After norma 2, Natsumi should look to be passive, unless the opponent poses little risk of KOing her and she is likely to deal damage
Dinner triggers Natsumi's passive making it a good way for her to gain stars if she cannot land on people, and she does not have her hyper.
Rbits makes Natsumi very likely to take 1 damage, which she will heal off. It also cannot be used against her well since using it makes the user unable to evade, guaranteeing Natsumi stars if she isn't KO'd. Its 3 star cost also means that Natsumi is able to still make a profit if she was able to deal damage if she used it.