Spencer has never been seen in Salem. He was only mentioned once by Julie. Apparently Steven had Spencer with a model in Europe. Spencer was supposed to come to Salem as a young man but the storyline was scrapped. He was never given an ornament. It just showed up with the newer ornaments a few years ago, along with new ones made for Steven (they misspelled his name as Stephen), Sandy (Tommy Horton's daughter) and Janice, since those 3 either broke or were reused.
Steven was last played by Stephen Schnetzer, probably better known as Cass Winthrop on Another World. Steven was a con artist/crook. Here he is with Julie. So Hope has two half-brothers, Steven (by Addie) and Dougie LeClair (by Doug).
Janice was Mickey and Maggie's foster daughter. She was eventually returned to her bio mother, Joanne. The character returned in 1987 as an adult, who was now a doctor. She got involved with both Mike and Bill Horton. Janice was killed by Jack's adoptive dad, Harper Deveraux (when he was the Riverfront Knifer). She died on the operating table as Bill and Mike tried to save her.
Janice's original ornament was red. I believe it was reused as Sarah's ornament after Sarah's original ornament apparently broke. Janice's ornament wasn't seen or mentioned for decades, then this new one was made a few years ago out of the blue and Maggie put it on the tree.
Here's the last time Janice hung her own ornament (the red one), with Bill, Melissa and Tom behind her: