Update: the whole ordeal is completed at 9:44am with an extension until the 30th of April.
Things I took with me:
Copies of all passport pages with my signature at the bottom
Completed TM7 form printed off the website
Passport photo
Embassy letter
Original passport
They have a station set up for printing/copying/photo printing just in case. They can also provide you with any of the forms that you are missing.
Overall the experience was actually great. The staff were very helpful and once you get to the waiting area on the second floor you are in the shade with a bit of a breeze blowing through.