CataclysmicOreo's page

If a character has a disease, bubonic plague for example, nap stack allows them 4 checks to cure themselves for 8 hours of sleep as that 8 hours counts as 4 days per the spell.
Does that also mean bubonic plague triggers its effect 4 times as it has a frequency of 1/day? It's a little vague in the spell description and it wouldn't really make sense to me if sleeping better somehow also sped up the spread of a disease, but one of my players thinks this is how it works so I thought I'd check.

Spell-Drinker: http://www.d20pfsrd.com/feats/general-feats/spell-drinker

1. It says "The magic that cannot harm you..." Despite this line being flavor text, does that mean if a spell causes damage even on save, you do not gain the benefits of this feat or is it just flavor?

2. If you do gain the temporary HP on a save but still take damage, is it applied before or after the damage? If it's applied before I'd assume that if the damage is still enough to take away the hit points even after saving,
you'd immediately lose the bonus to saving throws the feat grants you.