Q58: If a funny and cute killer gnome uses an illusion spell to imitate the effect of a spell that allows a saving throw (for example a fireball ), does the target needs to save twice? Is there someway to remove the second save if it's still there?
The Shadowcraft Mage Shadow Illusion ability says "The altered spell functions identically to the
shadow conjuration or
shadow evocation spell, except that the spell's strength equals 10% per level of the figment spell used." So you follow the rules for those spells, except for the strength involved. Both of those spells allow a save against the Shadow X spell
and a save against the spell being faked, as well as spell resistance if any (Shadow Conjuration even allows spell resistance if the faked effect normally doesn't).
I'm not aware of any way to remove the second save, but I think the point there is to either get your saving throw DCs impossibly high so having two saves doesn't matter, or to get your quasi-reality percentage up so high that your illusions are more real than the genuine article, and then keep your save DCs low so disbelief is easy.