The obvious person Arwen would want to speak to in Tol Eressëa is her mother Celebrían. It is one way to bring Celebrían into the frame not in flashback. Of course, the Tower Hills are nowhere near Lothlorien, so that's a long trip to make. If the elf going to the Havens in the frame is going 'in real time', Arwen could decide to accompany her to the Havens, and thus have adventures all across Middle Earth rather than be cooped up in Lothlorien.
We would lose Celeborn if we did it this way; he'd be in the first (say) 3 episodes, and then after Arwen returns to Lothlorien towards the end of the Season. So, if the goal was to have Celeborn a consistent character throughout all 13 frame episodes....no go. But we've mostly been focusing on Arwen as the primary character anyway, so that might not be a problem. The twins could insist on accompanying her as 'escort' and thus we could see that they haven't quite gotten over losing their mother, either.
There are definite reasons to consider using the palantir at Elostirion.
We would lose Celeborn if we did it this way; he'd be in the first (say) 3 episodes, and then after Arwen returns to Lothlorien towards the end of the Season. So, if the goal was to have Celeborn a consistent character throughout all 13 frame episodes....no go. But we've mostly been focusing on Arwen as the primary character anyway, so that might not be a problem. The twins could insist on accompanying her as 'escort' and thus we could see that they haven't quite gotten over losing their mother, either.
There are definite reasons to consider using the palantir at Elostirion.