It's said that the Eclipse will bring unique stealth components to the game. Will older stealth ships like the Sabre and Hornet Ghost be updated to include these stealth components, or are they specific only to the Eclipse?

It is very rare that these items are hull locked and currently none of the default items (i.e. power plants and shield generators) are tied to a specific ship such as the Eclipse. As mentioned previously, we have the stealth class of items which provide significant benefits to signature reduction and applicable ships will either come default with these or be able to equip them.