yes,phantasms do damage (iDuelist is a phantasm, and is my preferred one. IN BW2, it was bugged, and was the highest DPS in the game ), and clones are simply copies that are spawned with scepter spamming or a few other utility skills. They are distinguished from one another in the skill description.
the clones do 0 damage--they simply sit there and look like you, assuming you sit there, too. the use is actually a little bit better, as they are actually drawing aggro, randomly, from NPCs. They weren't doing this very well in earlier builds of the game.
and the shatter skills--yes, my gripe with them is that the damage they do is so miniscule, and the conditions applied so limited in time, that they entire functionality seems to be not very useful. especially when all are shattered at once, on one targeted enemy--and they still do practically no damage. I will have ot see at higher levels, as my main gripe at the moment is that it is not a very good leveling build. there is also the signet (decent passive one that grants meager vitality to your illusions) that when activated, refreshes yoru shatter skills. I don't see this as very useful, as all of them shatter at once, and you need some time to get them up again, so you're generally just refreshing one of 4 shatter skills?
could be my playstyle, as I just don't see the real use for shattering. maybe I should be more spammy with clones and instant shatter? I was doing this in BW1--when the dual clone skill was easier to obtain (I have it again), and there was more damage. for this, I really like scepter + clones utility, + iDuelist, as you constantly had a stream of exploding illusions....but they were actually doing some damage, then. :\