You're missing a link to Interdependent Chess, and I left a comment on that page about the name of Guardian being used for the Berolina Steward in Lt. Obert's Decimal Chess from the 1870's. I didn't give double moves to the Steward and Guardian in Interdependent Chess, probably because it was on a small board. In Decimal Chess, Obert gave his Guardian a double move not only from its starting square but also when returning to it. Pritchard's description does not make it clear whether either Guardian has a double move returning to either Guardian's starting square or whether each Guardian gets a double move only to its own starting square. I came upon the same name as Obert did by coincidence, as I did not know about his game until later.
You're missing a link to Interdependent Chess, and I left a comment on that page about the name of Guardian being used for the Berolina Steward in Lt. Obert's Decimal Chess from the 1870's. I didn't give double moves to the Steward and Guardian in Interdependent Chess, probably because it was on a small board. In Decimal Chess, Obert gave his Guardian a double move not only from its starting square but also when returning to it. Pritchard's description does not make it clear whether either Guardian has a double move returning to either Guardian's starting square or whether each Guardian gets a double move only to its own starting square. I came upon the same name as Obert did by coincidence, as I did not know about his game until later.