VA Maintaining Internal Systems and Strengthening Integrated Outside Networks Act of 2018 or VA MISSION Act of 2018 This bill consolidates Department of Veterans Affairs (VA) community care programs, revises other VA health care programs and facilities provisions, and makes appropriations for veterans care. The bill establishes the Veterans Community Care Program to furnish hospital care, medical services, and extended care services through certain non-VA providers to veterans who are enrolled in the VA health care system or otherwise entitled to VA care. The VA may enter agreements with non-VA providers to furnish veterans with care that is otherwise not feasibly available. The VA shall: (1) establish standards for VA health care quality and for non-VA care in areas of VA expertise, (2) prohibit rehiring previously-removed VA providers, (3) provide prompt payment to providers, and (4) establish opioid prescribing practices for non-VA providers. The Veterans Choice Program is terminated after one year. The bill establishes the Center for Innovation for Care and Payment. The VA may: (1) provide care for the live donor of a transplant for a veteran, and (2) carry out a Specialty Education Loan Repayment Program and other actions to recruit health care professionals. The VA family caregiver program is expanded. The Office of Management and Budget shall review each enhanced-use facility lease. The bill establishes pilot programs for medical scribes, mobile deployment teams for underserved facilities, and graduate medical education. The bill extends VA pension reductions for Medicare-covered veterans in nursing homes.