Who knows? Some artist had some idea about what symbols he wanted in the paintings. I've never seen any haloed children in any depiction of the Stations of the Cross, so it's not some common thing that we're all supposed to 'get'.
I think they're "angels." Here is why: "there can't be any saints yet". Saints are people who have died and gone to heaven. Since during the Stations of the Cross the gates of Heaven" are not open yet", there can't be any little children saints to come down and dig a garden or whatever they were planning with those shovels. Not any child saints could exist yet, not even the Holy Innocents, who would have landed in the Limbo of the Fathers.
Everyone who died before Jesus opened the gates of Heaven went to the Limbo of the Fathers. Unless they went to Hell. I think if they were headed to Hell, they went straight the Hell. I'm not sure about that, but that seems like the expedient thing to do. Certainly all the "good" people went to the Limbo of the Fathers. Then, when Jesus died on the cross and before He rose on Easter, He went to the Limbo of the Fathers and let everyone out. The Limbo of the Fathers closed.
Then Limbo was re-opened for the unbaptized babies and the Aborigines. I was under the impression that Limbo was closed for good after Vatican II, but it seems the jury is still out on that one. The official word is that the Church "hopes" Limbo is closed for good and that God in his mercy has accepted the little unbaptized babies (and the Aborigines and dead Native Americans who lived before the North American Martyrs tried to save them) into heaven. We just don't know.
And I just don't know who those children could be if they are not angels.
The bigger mystery, in my opinion, is what on earth they are doing with those shovels! Surely they aren't going to help dig the hole in which to place the cross! Perhaps they are, since Jesus' death and Resurrection is very important and must be accomplished.
I wouldn't put it past some artist to stick some child saints in there, even though they couldn't really exist yet. Here's a painting called "The Triumph of the Holy Innocents" in which the blessed children are having a fun time accompanying the Holy Family on their flight to Egypt. I'll bet not one of them asked, "Are we there yet?"
Or perhaps the artist had a fever at the time in which he painted that panel in your church. You might want to just try and track him down and ask.
Source: esoteric-soup.blogspot.com
