For best results, use day-old bread as it absorbs the custard mixture better without becoming too mushy.
You can prepare the bread soaking step up to 24 hours in advance for deeper flavor absorption.
Substitute fresh pineapple juice for canned if available, though canned provides a consistent sweetness.
The ambrosia salsa can be made up to a few hours ahead; add the coconut just before serving to maintain crunch.