Simple Q&A D&D 3.5 (by RAW) XXII

[Curmudgeon]

A 710

... if a creature’s saving throw succeeds against a targeted spell you sense that the spell has failed. You do not sense when creatures succeed on saves against effect and area spells.

When a spell fails, the caster does not know specifically why it failed. In most cases, they don't even know if the spell failed.

a) , b), d), e), f): No clue at all, including no knowledge whether the spell succeeded or failed unless the spell's result is apparent (such as Fire Storm).
c): You'll know the spell failed, but not specifically why.

A 711 Yes.

There's no exception for spell damage with hardness, unlike with damage reduction.

A 712 Yes.

There's a feat called Aberration Blood, but Inhuman Reach does not specifically call out that it refers to that feat. "<whatever> Blood" is also the standard terminology for qualifying heritage, such as "Elven Blood". Because "Aberration Blood" could refer to either the feat or the heritage, both meanings are valid.