Beckio, the baby would probably be eaten the first day. Many times it's not even safe to put them on the floor near each other. Beardies have no maternal/paternal instincts and get pretty excited at " large" prey items, and that is exactly what a baby beardie looks like to them...something to eat.
GG1, sometimes 2 female babies that are the same size can be raised + housed together, usually you need to get them at the same time rather than introduce one after a while. But even then there can be fighting and serious bites that maim.
But a baby can never, ever be housed with an adult and it's risky to put them near each other.