could a construction with "ter" work here as well? That seemed the most literal translation for me.
Yup, since we have "to have" in the sentence. I found a bit weird "have been" used with 'today'
In English it makes perfect sense, since today is not over yet.
What would use with ter in portuguese? "ter sido" was rejected. "ter ficado"?
here you dont use "ter+participle", just the past. Não estiveram may mean "pass by, drop by" and "não ficaram" may refer to an extended period of time.
Can i use the Present Perfect when i say the period? For example (Yestarday, today, last week)?