In this answer, I learned that with "correct" French, you aren't supposed to use possessive determiners for body parts ("ma tête, mes jambes"), but instead use a definite article ("la tête, les jambes").
The reply you quote didn't clearly stated this "rule1" only apply to sentence like:
Elle aime masser ses jambes.
This rule does not take into account exceptions that are dictated by context in which various parts of the same sort have to be differentiated.
In the last sentence, if the article is used there is no way to ensure whose hands are meant.
In the second sentence, "mes" (jambes) could have been "les": the rule is not applied in this case (...
With expressions of clock time, use the preposition à to say (at) what time. You can leave out the "at" in English, but not the à in French. It answers the question « À quelle heure ... ? »
À quelle heure ?
Demain on a rendez-vous à 13h30. On va dîner à
Je me lève toujours à cinq heures.
For expressions of repeated days or ...