The Russians will slaughter them like baby seals - if they want to. Folly to think these kids have a chance in real combat. Remember the Russians have different rules of engagement than we do.
They will commit many atrocities, yes. They have a long history of no restraint when engaging in civilian population, whether under the Tsar, or the Politboro, or the Russian Federation leaders. Problem is, that creates a bit problem in the PR war, because this will all be televised and uploaded and very graphic, and anyone left standing even remotely giving Putin a pass is going to look awfully foolish.