Not to many spells and in the video they talked about most.
Douse Light is a cool cantrip you could have in your pocket against creatures without darkvision. Gaining advantage on your attacks because your targets can't see seems like a sneaky way for Talin to get in some good sneak attack damage.
If your going melee, then the mirror image and blur ability will help in combat.
Up to you but I think the spells are what you were looking for thematically even though some may not be as powerful as others. Thing is you only get a few spells to start. You have Ice Knife and Shield listed now. You could take and trade the Ice Knife for Cloying Darkness - it doesn't do as much potential damage but it is a cool spell.
[sblock=Cloying Darkness]
1st-level necromancy
Casting Time: 1 action
Range: 30 feet
Components: V, S
Duration: 1 round
You reach out with a hand of decaying shadows. Make a ranged spell attack. If it hits, the target takes 2d8 necrotic damage and must make a Constitution saving throw. If it fails, its visual organs are enveloped in shadow until the start of your next turn, causing it to treat all lighting as if it’s one step lower in intensity (it treats bright light as dim, dim light as darkness, and darkness as magical darkness).
At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, the damage increases by 1d8 for each slot level above 1st.[/sblock]