Chance me for Duke ED

Come from a high school that gets in around 8 to 10 students into Duke, am Asian, and am looking to probably major in Physics + something related to humanities in case any of these matter.
GPA: 4.38
SAT: 1600, Math 2: 800, Physics: 800, ACT: all sections 36 except for science which was a 34, composite: 36
Taken SAT twice and ACT once but I do not believe that matters since Duke is score choice
Taken a total of 12 AP/IB courses in 10th and 11th grade combined and am involved in the IB program at my school. Will be taking 6 AP/IB courses in senior year.

Extracurriculars: fairly rigorous, will elaborate more on this in a day or two

A couple of questions apart from chancing me for Duke ED:

Is it worth taking the ACT again in order to get science to a 36? Am fairly confident this will happen with a time commitment of about 3 to 4 hours before the ACT.
What percentage of the application will the essay be? Not looking for an exact figure here but an approximate percentage would be appreciated.
Does Duke automatically take into consideration all the extra work done by IB students like the CAS hours, extended essay, etc or should I mention that somewhere?
Will applying as an intended Physics major hurt, help, or not affect my chances as opposed to applying undecided?