I LOVE the way these crawls are looking. I like the "acting Senator" suggestion because in a word it activates her role -- the Queen is doing something special -- that's why she's a target.
But I point out that saying "Ten years after Palpatine rose to power in the Galactic Senate, unrest once again pervades the Galaxy" has a grammer problem. If we say "after" Palpatine "rose" to power, it implies the second half of the sentence should also be past tense -- "after" he "rose" to power, unrest "pervaded" the Galaxy -- it implies a past tense to the whole sentence.
"After Jim rose from bed, unrest once again pervades the galaxy." Those tenses don't agree.
"After Jim's rise from bed, unrest once again pervades the galaxy." That works.
Ten years after Palpatine'S RISE to power... objectifies the verb and puts the sentence in the present.