Guild Wars 2

The Illusionary Warden skill does not credit kills towards the Focus Mastery achievement.

I suspect the same for Illusionary Duelist and Pistol Mastery, although I haven’t tested duelist specifically.

No illusion kill counts as weapon master achievement.

Nretep.2564:

No illusion kill counts as weapon master achievement.

I believe it should — they are skills which originate from specific weapons.

Honestly every weapon for every profession should contribute towards the mastery achievements. I believe there are a handful of weapons which cannot tick the associated mastery trait — mesmer focus is one of those.

Well, I don’t know how reflects or “pull-off-cliffs” are counted, but for phants …

They’re explained as mesmerizing your opponent. They are not real, but make the target think it’s been harmed (yet, it works on buildings). So it’s not actually your weapon which does the kill.

So, illusions do not “originate from specific weapons”. It’s the technical implementation, but not the designed one. Illusions can come from multiple sources, not bound to weapons. There’re even phantasms without weapon (pRogue, pDisenchanter, pDefender), so which weapon do they credit to?
If you look at staff phants, they wear abyssal scepters …

Technically, I’d also prefer weapon-specific phants to count towards the weapon, but that’s a design choice (well, most probably technical work) of ANet.

Utility skills don’t count towards any weapon so no issue with Defender and Enchanter.

For the weapon skills to “count” against the associated mastery two things have to happen:

1. Weapon skill needs to do damage
2. Something needs to die as a result of that damage

The phantasms don’t do damage on summon so I think they violate “rule” number 1 above.

I like to think it’s a bug that phantasms for a weapon don’t count towards the mastery — but honestly it’s probably a “design oversight”. Regardless I think it should be fixed — it’s possible this topic is more of a suggestion than a bug. Until ANet says otherwise, I’m content leaving it as a bug report.