Hi Sandra,
Edward Creer born Andreas ca 1778 - 1781 was the husband of both Esther Cubbon and Margaret Howland - and as you know the family settled and farmed at Ballavastyn in Andreas.
There were no Creer families living before then in Andreas and so no obvious or possible parentage can be deduced this way. However there was a marriage of a William Creer to a Bahee Crow in Andreas on 13th July 1782. The records tell us that Bahee Crow was a minor at the time of the marriage - and perhaps one could suppose that Edward might have been their first child but born out of wedlock. We know that William and Bahee had other children and so the marriage persisted - and the family lived in Andreas - the only Creer family to be doing so.
I think that this is a strong enough coincidence to suggest that Edward was the son of William Creer and Bahee Crow. However there are a number of William Creer born in other parishes some 20 years before - and it is not possible to deduce who his parents might have been.
cheers
John