A member of the Wheaton Plaza facebook page posted a picture of the water fountain at Wheaton Plaza:
Great photo. Thanks for posting it. This is likely an early photo of the fountain, judging by the clothing worn by the people.
The fountain was in a location known then as "Mall Central" or "Mall Center". The main entrance to Wheaton Plaza would be immediately to the left in the photo.
The photo faces East toward one of the two story "End Stores", Woodward and Lothrops (aka Woodies). Today this is a J. C. Penny's store.
Behind the photographer would be the area where the girls were seen near the Orange Bowl Pizza take out and beyond that, the other End Store, Montgomery Wards (now a Target store occupies the Wards space)
The Fountain marked the area of a "T" junction, just to the viewer's right in the photo. This was known as the "Plaza South" section as indicated in the sign.
Note the overhead covering of the fountain area and that the rest of the avenue is open to the weather, except for covered walkways on either side, close to the shops.
It was at or near this fountain that the Easter Bunny display was located, and where Sheila Lyon was seen by her brother Jay, and by another 13 year old boy who knew her.
Note that the fountain in this photo has a circular railing around it and a metal structure in the middle of it. A previous photo posted does not have any metal in or around the fountain.