If it turns out St Mirren were at it - although that would be difficult to prove - then I think a 3 - 0 forfeit would be fair under these specific circumstances. That has to come from the SFA, however, which is another process that needs to run its course.
I can't imagine it would be possible to prove they were at it, however, so I imagine that the SPFL being the SPFL will just hand out some token punishment, and suspend even that.
Meanwhile, the inevitable chaotic end-of-season comes another week closer.