So, let me try to understand your points, starting with Dairfaron:
Spell Trigger and Spell Completion items require that the spell is on your spell list. A spell slinger has no 0-level slots, but still has the spells on his list.
So, your claim, as far as I understand, is the removal of the Cantrip Class Feature keeps intact the 0 level spells in the spell list, but the Spellslinger has no way of accessing them.
As for LordKailas' Point:
Since spellslinger wizards can't cast other zero level spells no.(...)The archetype modifying your class needs to be taken into account when evaluating what your "class" is. Otherwise it screws over every archetype that lets you cast spells from a different class.
So, your claim is removing the Cantrip Class Feature also Removes the spells from the spell list... I've taken some time to think about screwing over archetypes with a similar ruling, but I'm coming up blank, and I would like an example. Also, the loophole with classes not being able to cast the spells being able to use spell trigger items may apply, noted here:
Spell trigger items can be used by anyone whose class can cast the corresponding spell. This is the case even for a character who can’t actually cast spells, such as a 3rd-level paladin.
So, from my understanding, it seems like it comes down to whether or not Removing the Cantrip/Orison Class Feature removes 0 level spells from the list, or if this counts towards the "Can't cast spells, but in the right class" Loophole. So, here's the wording:
Wizards can prepare a number of cantrips, or 0-level spells, each day, as noted on Table: Wizard under “Spells per Day.” These spells are cast like any other spell, but they are not expended when cast and may be used again. A wizard can prepare a cantrip from an opposition school, but it uses up two of his available slots
So, thoughts?