Keago is charged with seven charges of violating articles of the Uniform Code of Military Justice, including sexual assault.
Grazioplene, who has been incarcerated for 18 months, will serve no additional jail time as part of the plea agreement.
Army Pvt. Ethan Phelan Melzer submitted his plea in a U.S. District Court, Southern District of New York.
The U.S. Court of Appeals for the Armed Forces is the last stop before military appeals battles make it to the Supreme Court.
The NCIS issued a warning about the drug activity, which they say is largely taking place on the dark web.
The 64-page complaint was filed in the U.S. District Court for the Eastern District of North Carolina.
Block was shot and killed Aug. 16, 2007 by Staff Sgt. Paul Brandon Norris, who then turned the weapon on himself.
Nine Army families allege that their on-base, privatized housing sickened them and destroyed their belongings.
Until Monday's ruling, it was legal in more than half the states to fire workers for being gay, bisexual or transgender.
The suit had been filed against Defense Secretary Mark Esper, challenging the military's current transgender policy.