Is failure to comply with evacuation procedures illegal?
No. The intent of the statute involves "assaulting or intimidating" a crew member. Passively failing to obey a crew member has no criminal liability nor does disobeying generic safety guidance given by crew members or aircraft literature.

The actual statute reads like this (49 U.S.C. § 46504):


  An individual on an aircraft in the special aircraft jurisdiction of
  the United States who, by assaulting or intimidating a flight crew
  member or flight attendant of the aircraft, interferes with the
  performance of the duties of the member or attendant or lessens the
  ability of the member or attendant to perform those duties, or
  attempts or conspires to do such an act, shall be fined under title
  18, imprisoned for not more than 20 years, or both.


Normally, disobeying a crew member generally has the effect of getting the passenger kicked off the flight. Note that a captain can remove any person for ANY reason from a flight, nor does the captain need to give a reason. Of course, if the flight is in progress, then removal is not an option.

(Also, note that this answer is for the United States only. In authoritarian/Salic law type places like France or Germany, they have laws that generally make it criminal to disobey authorities, which is different than the United States.)