What is Clairvoyance/Detect Life under?

Alteration I believe.

Detect Life is under Alteration.

Clairvoyance under Illusion.

What perks would lean towards these abilities that I could use?

No direct perks. Inderect perks would include silent casting, and whatever their skill requirement is to half their cost.

Edit: though I believe both are silent spells anyway aren't they?

Detect Life wont be covered by the Stability perk (increases duration) as it is a hold to spell cast. Other than the reduce magicka cost perks and quiet casting, I doubt there are any perks that'll affect it.