I had a specific memorial day question:
Is it only for those that died in battle? Or is it expanded to those that died in service to their country in other forms?
Neither. "commemorates the men and women who died while in the military service"
Would someone who died in a training mission but not in an active war?
yes, if in the military
What about someone in the CIA who died on an undercover mission?
no
What about a bodyguard killed protecting the president?
If they were in the military (e.g. a Marine) then yes. If serving in the secret service, no.
What about an astronaut that died in a shuttle explosion?
If still serving in the military but assigned to NASA (such as Dick Scobee) then yes. If not in the military then no.