ok @papa-pepper, am glad you found it delicious ;) the prickly skin can ripen further as it can get a bit yellowish, but not so much as it can over-ripe too, ruining the fruit.
the left-over smaller flesh can be made into jams. and the seeds are edible yes, boiled or roasted.
jack fruits have a sticky sap, so we use oil in our hands when eating and when using the knife. saves a lot of trouble when cleaning-up.
the seeds when dried can sprout into saplings when in a moist soil.