Answer can be found here. In sum: No, they do not, but caveats apply.
If a Neko or a Neko couple have a youngling, and they're currently not on active duty (they're on the Prestige system or salary, taking time off from their service), does the Neko youngling have to serve in the Yamataian military?
The ethos is "the Empire gave them life," but for the youngling, that's not the case (directly, anyway). Especially with NH-33, who can produce younglings with basic programming instead of the military suite.
That leads me to think that younglings are not duty-bound to serve, even if some want to.
If a Neko or a Neko couple have a youngling, and they're currently not on active duty (they're on the Prestige system or salary, taking time off from their service), does the Neko youngling have to serve in the Yamataian military?
The ethos is "the Empire gave them life," but for the youngling, that's not the case (directly, anyway). Especially with NH-33, who can produce younglings with basic programming instead of the military suite.
That leads me to think that younglings are not duty-bound to serve, even if some want to.