No, you can ignore Charlotte quest and go direct to the magic key and take it. Without go to the Elves Elder and searching to Charlotte. ^^

Only you need a directing monster from the snow cave in Snow Isle.
And then take magic key and then go to Inca and battle them to get Eva.
You have Eva, without Charlotte, and finish! ^^

It is not 1% of Charlotte Quest, besides Directing Monster is not a part of Charlotte Quest, but Angkor Wat Quest. That is different.