If you have multiple execute package tasks which have checked as part of
their own package properties "use transactions" but the main package does
not use transactions and the workflow property of the execute package task
does not join the main package transaction does this mean that each
individual package uses its own transaction and since the main package does
not use transactions that each execute package task will use its own
transaction? or does it mean that since the main package does not use
transactions that this will override the individual package propery setting
of use transactions?

No theory please.