I was just rereading my copy of Into the Shadows (the 1992 Roc reprint, not the original 1990 printing from FASA.) As I was reading Tom Dowd's story, A Plague of Demons, I noticed the references to the Universal Brotherhood metaplot. Was this story added to the Roc reprint, or was it in the original FASA edition of the anthology? Because, even allowing for development and playtest, it seems odd that this story would have been hinting at a metaplot that had yet to be released. (Yes, I know that Queen Euphoria laid the groundwork for the later releases related to the UB, but as I recall, it didn't mention the Brotherhood by name.)

IIRC it was in the original.

The UB was a background feature in SR well before the Universal Brotherhood adventure/exposure book was released. Check out the ad in the old London SB!

As far as I recall, Plague of Demons replaced another story from the 1st Into the Shadows anthology.

As for hinting at plots yet to to be written [I was reading about this on a website that now seems to be gone]...
...People like the early authors of SR fiction frequently referred to things that they wrote up later.

Whether they knew in advance about things they were going to write up, and it was just a teaser...
...Or they had a vague idea which they mentioned, and then filled out later [in a supplement, perhaps], is debatable.

Foreshadowing is exactly what happens with metaplots...
...Unrelated events and hints that become more important later.

I have both editions of the book.

Into the Shadows, FASA 7601, ISBN 1-55560-118-9, contains:
Cover, by Jeff Laubenstein
Into the Shadows, By Robert Charrette
Graverobbers, by Elizabeth T. Danforth
Tailchaser, by Paul R. Hume
Striper, by Nyx Smith
Whitechapel Rose, by Lorelei Shannon
Turtle in the Tower, by Ken St. Andre
Free Fall, by Tom Dowd
Would It Help to Say I'm Sorry, by Michael A. Stackpole
It's All Done with Mirrors, By Michael A. Stackpole
Timeline
Contributors

Into the Shadows, ROC 5189, ISBN 1-451-45189-9, contains:
Cover, by Keith Birdsong
A Plague of Demons, by Tom Dowd
Graverobbers, by Elizabeth T. Danforth
Tailchaser, by Paul R. Hume
Striper, by Nyx Smith
Whitechapel Rose, by Lorelei Shannon
Turtle in the Tower, by Ken St. Andre
Free Fall, by Tom Dowd
Would It Help to Say I'm Sorry, by Michael A. Stackpole
It's All Done with Mirrors, By Michael A. Stackpole
Glossary of Slang: 2050
Contributors
Timeline

Minor details have also been changed (the prologue, a single Illustration, Robert Charette removed from Contributions, Liz changed to Elizabeth).

Into the Shadows, By Robert Charrette was used as a prologue in Secrets of Power, volume 1, Never Deal With a Dragon (minor details changed)