Victoria, yes. Stephen, no. I had to dig out my copy of Clarence and check, but it seems to me Harrison's evidence is so circumstantial that I question whether it can be called evidence at all. Harrison's reasons are too long and complicated to go into here, and they've generally been discredited. So I'll offer just one example.
A couple of years before the murders, Stephen suffered a severe blow to the head. His behavior thereafter became increasingly bizarre, and he spent his final days in an insane asylum. Harrison points out the murders stopped when Stephen was committed. Yes, that's true, but they'd stopped three years before he was committed. Harrison also says Stephen escaped long enough to commit one more murder, one not included in the usual list of Jack's victims, etc. etc.
Everybody wants to solve this case, but no one ever has.