1. Yes, timey-wimey-wibbly-wobbly. It doesn't make a lot of sense and it flies in the face of suspension of disbelief, but yeah. In the lore, just one year.
2. Tempering does not require the primal to be summoned. Otherwise the primals themselves wouldn't have nearly enough followers to sustain them. This is why beast tribes such as the Amalj'aa and Sahagin take slaves and prisoners. Using "sacred" items blessed by the primal's corrupting influence when it was corporeal, they are able to temper new followers without having actually resummoned their gods. In the case of the Amalj'aa, they have their sacred flames which they hold their slaves in until their minds temper. The Sahagin take thalassocratic prisoners and "drown" them in the waters around their summoning pool. It's unclear for some of the other primals, though the Sylphs are always attempting to capture non-tempered sylphs and convert them in some way. I'm not sure what method the Qalyana used, but it was likely in a similar fashion. The primal only has to be summoned once to corrupt something that can be used later to temper others.
2. Tempering does not require the primal to be summoned. Otherwise the primals themselves wouldn't have nearly enough followers to sustain them. This is why beast tribes such as the Amalj'aa and Sahagin take slaves and prisoners. Using "sacred" items blessed by the primal's corrupting influence when it was corporeal, they are able to temper new followers without having actually resummoned their gods. In the case of the Amalj'aa, they have their sacred flames which they hold their slaves in until their minds temper. The Sahagin take thalassocratic prisoners and "drown" them in the waters around their summoning pool. It's unclear for some of the other primals, though the Sylphs are always attempting to capture non-tempered sylphs and convert them in some way. I'm not sure what method the Qalyana used, but it was likely in a similar fashion. The primal only has to be summoned once to corrupt something that can be used later to temper others.
