Ants and daffodils might, by some definitions, have preferences--but it wouldn't be necessary for a FAI to explicitly consider their preferences, as long as their preferences constitute some part of humanity's CEV, which seems likely: I think an intact Earth ecosystem would be rather nice to retain, if at all possible.

The entropic contribution of ants and daffodils would doubtless make them candidates for early destruction by a UFAI, if such a step even needed to be explicitly taken alongside destroying humanity.