In Star Wars: X-Wing each wave of new ships brings upgrades that you can use on previous ships. In some cases this even include fixes in the form of upgrades or things that would be foolish not to use often.

Is Armada going with same route? Are the cards that come with Home One and the Imperial Star Destroyer likely usable on the CR-90 and Victory Star Destroyer?

Yes, assuming they have the right upgrade slots on the ship. All cards will be useable on any ship that has the right slot

Yeah, but there seems to be (luckily) a little more cross-over with cards being in multiple sets. And luckily, no upgrades in the fighter/rogue sets. So you don't NEED to grab those as much as you normally would in most x-wing waves.