RAW Mage Armor and Shield work just like normal armor and shield for things like Touch AC/Flat Footed AC.
The only exception are incorporeal touch attacks specifically. Mage Armor/Shield effectively turn touch attacks into normal attacks for that character and AC calculation.
To count as incorporeal touch attacks, the monster's attack entry should say
quote:
Melee incorporeal touch
Though because "editing" exists, there may be some creatures who have the incorporeal subtype and touch attacks that aren't correctly listed as such.
And yes, if the incorporeal creature was casting shocking grasp, mage armor and shield would not apply because they don't apply to normal touch AC, just incorporeal touch AC.
God I love the complexity of 3.5/PF sometimes. I really warms my semantics loving heart.