Do these take a long time to compost, if so is there some way to speed up the process. Or should I leave them out of the compost bin altogether?
The crown leaves likely contain a semi-valuable fibre; there is a variety of pineapple specifically grown for those fibres. They are very fine and durable, so the leaves will, yes, take a while to break down. Pulling the crown apart into its separate leaves would help to break them down more quickly. You could consider using the crown to propagate more plants rather than compost it.
As for sheath and kernel, I presume by these terms you mean the inedible core and the outer skin? These would appear to be a prime candidate for worm- or vermi-composting. If you can chop up the core somewhat and put the outer shell, intact as a cylinder packed with core bits, into the vermi-compost bin this is the kind of environment that worms will congregate in and take care of the breakdown for you.