Drow Nobility and Shade Magic

[Xuldarinar]

A question of interaction. If a drow takes the Shade Magic alternative racial trait (it replaces their standard spell-like abilities with cloak of shade, dusk of twilight, and ghost sound);

Can they take the Drow Nobility feat?
If yes; When you take Improved Drow Nobility, do you get usage of dancing lights, deeper darkness, faerie fire, feather fall, and levitate all at 2/day in spite a good portion of those not being previously possessed?

[Red Fel]

A question of interaction. If a drow takes the Shade Magic alternative racial trait (it replaces their standard spell-like abilities with cloak of shade, dusk of twilight, and ghost sound);

Can they take the Drow Nobility feat?
If yes; When you take Improved Drow Nobility, do you get usage of dancing lights, deeper darkness, faerie fire, feather fall, and levitate all at 2/day in spite a good portion of those not being previously possessed?

Well, let's go through the pieces.

First, Shade Magic is an alternative racial trait for Drow in Blood of Shadows. It "replaces a drow's normal spell-like abilities" with Cloak of Shade, Dusk of Twilight and Ghost Sound.

Next, Drow Nobility requires "able to use drow spell-like abilities." So, possibility #1: If the "Shade Magic" trait replaces the "Spell-Like Abilities" trait, then you no longer have "drow spell-like abilities," and thus cannot take Drow Nobility.

But let's assume for a moment that the SLAs from Shade Magic count as "drow spell-like abilities." Well, let's go through what DN gives you - gain Detect Magic as an at-will SLA, and add Levitate and Feather Fall to your 1/day SLAs. So if Shade Magic does work with DN, there's no change there, and no conflict.

So then we go on to IDN. Well, IDN points to specific SLAs. It does not say "You may use your SLAs 2/day." It says "You may use the following SLAs 2/day," and gives a list. It also says that your Darkness SLA changes to Deeper Darkness and may be used 2/day. So this has absolutely no impact on the special SLAs you gained from Shade Magic - it doesn't give you extra uses of Cloak of Shade, Dusk of Twilight, or Ghost Sound. Likewise, GDN points out specifically what SLAs benefit from it; Shade Magic doesn't benefit.

Further, and this more directly answsers your second question, neither IDN nor GDN gives you SLAs - they simply give extra functionality to the SLAs they presume you have. They give you additional uses of what you have; you don't have it, you don't benefit.

Really, the only benefit a Shade Magic Drow gains from the Drow Nobility line is an always-on Detect Magic, plus at-will Levitate and Feather Fall. Again, that's assuming the fact that "Shade Magic" replaces "Spell-Like Abilities" doesn't turn it into a non-starter.

[Extra Anchovies]

I'm not finding Shade Magic on the PFSRD or Archives of Nethys. What's the source and/or exact wording? If it says it replaces the "normal drow spell-like abilities", then it's obviously putting non-normal drow spell-like abilities in their place. If it says "this replaces the Spell-Like Abilities racial trait", then you have a trait called Shade Magic instead, which means you don't have the drow spell-like abilities that Drow Nobility is looking for. Changing the contents of the spell-like abilities trait without removing it and putting a differently-named trait in its place still leaves you with those drow spell-like abilities, so you still qualify.