One interesting find in researching Trindles, is the probate of John Trindle, a merchant in Dublin in 1731. If our William followed normal naming rules in giving his son the name John, then his father should be John. A death for John in 1730/31 might explain why his sons would emigrate to America, where William is found in 1740. Family tradition states that he was in Philadelphia prior to 1740 learning the trade of a tailor.
Unfortunately the wills listed in the Will Registers do not exist and to date I have found no connections between John and William...but it is a quest to keep in mind.