Harry W. Colmery Veterans Educational Assistance Act of 2017 This bill revises education and related benefits provided to veterans, service members, dependents, and survivors. The bill amends the Post-9/11 veterans' educational assistance program to: remove certain time restrictions on program use; increase assistance for reservists, guardsmen, dependents, and surviving spouses and dependents; provide full eligibility for Post-9/11 Purple Heart recipients and certain reservists and guardsmen; provide an extra academic years' worth of benefits for STEM (science, technology, engineering, or mathematics) degree candidates; establish a five-year pilot program for high technology courses; restore eligibility for service members whose school closes in the middle of a semester; authorize funding to improve claims processing; permit assistance to be used at certain institutions that are not institutions of higher education; and pro-rate the housing stipend for reservists called to active duty. The bill authorizes the Edith Nurse Rogers STEM Scholarship to help veterans complete STEM degrees. The Yellow Ribbon program is extended to Fry Scholarship recipients (surviving dependents of service members who died on active duty) and certain Purple Heart recipients. (The Yellow Ribbon program helps veterans pay for higher education tuition and fee costs not covered by the Post-9/11 program.) The bill: (1) extends the Advisory Committee on Education, (2) increases survivors' and dependents' educational assistance, and (3) extends funding for state educational program approving agencies. The bill provides statutory authority for the veterans success of campus program which provides veterans with on-campus educational and vocational counseling. The Department of Veterans Affairs shall: (1) make a new determination regarding each denied veteran's claim for disability compensation in connection with full-body exposure to mustard gas or Lewisite at specified locations during World War II, and (2) presume such exposure unless there is affirmative evidence otherwise.