A Few Witch Questions

[ATHATH]

If a Jinx Witch Witch (http://www.d20pfsrd.com/classes/base-classes/witch/archetypes/paizo-witch-archetypes/jinx-witch-witch/) uses its Jinx-Eating ability, can it only use the spell as a spell-like ability once, or can it use it at-will? Does the SLA have to be used immediately, or can it be used at any point in the following hour?

Can Witch familiars take archetypes? If so, what happens if a Witch's familiar takes the School Familiar (http://www.d20pfsrd.com/classes/core-classes/wizard/familiar/familiar-archetypes/school-familiar-familiar-archetype/) archetype?

[Geddy2112]

It can be used anytime in the following hour as it follows the jinx eating rules. RAW I am fairly certain that at level 10 the witch can at use the SLA(unless they need a caster level check if the spell is not on their list or higher level) and can for an hour unless the spell is used to power another spell they have, or they fail the check.

Anyone with a familiar can take a familiar archetype, but the school familiar is useless for anyone but wizards or other archetype class that can get a school.

[Psyren]

Note that a Witch can pick up an arcane school via Variant Multiclassing, allowing their familiar to benefit from this archetype. The familiar ability that the VMC gives you will be wasted however.