Does this mean, "We are going after her (in a queue)," or does it mean, (We are going after her (to catch her) "?
Or could it mean both, perhaps?
Either the former, or "we are following her". The latter would be אנחנו רודפים אחריה.
The transliteration to Amir’s Hebrew is Anakhnu rodfim akhareha.
We are chasing her. (Rodef, rodefet).
Anakhnu holchim akhareha
So this is used both for after in time and for after in place?
Can this sentence also mean sequence: אֲנַ֫חְנוּ לֹא הוֹלְכִים עַד שֶׁהִיא הוֹלֶ֫כֶת, i.e. we wait, until she is gone, and then we go, because we do not want to be seen by her leaving.
I heard "אחרה" (no yud) in a movie, at least I think that is how it would be spelled. It sounded like "acharah" and the English equivalent was "get her!" or "after her!" (guards).
Is "acharah" probably an imperative form of אחריה?
Prepositions, such as אחרי don't have "an imperative form", only verbs do. You probably heard אחריה "achareha" with a very faint "eh", which is how most people pronounce it.