الْبَهَائِمِ is a plural referring to non-rational beings. Its adjective الْمُعْجَمَةِ appears in the feminine singular form, a common Arabic agreement pattern with non-human plurals. This is a short, useful grammatical observation from the narration itself.
The repetition of صَالِحَةً directs attention to two settings: the animal’s fitness when ridden and its suitable condition when used for food. A grammatical detail can make the practical point easier to see, rather than merely adding terminology.