Were there other children?
Were they all baptised in Falmouth?
Have you traced them to see where they went?
Did William witness their weddings?
Are there any wills in which William could have been a named beneficiary?
Did William join the army or the navy? merchant navy?
Did William commit a crime? Could he have been transported?
Did William and/or the family emigrate? America, Canada, South Africa, India, Australia, New Zealand etc