Please, no spoilers here! Answer simple without any hints or tips! Please, thank you!

I have a question I've asked previously but I didn't really get an answer.
Here we go..

I started as a Wood Elf and I love it.
Then I explored with spells and I love it.

But I want to keep a "window open" for being a stealthy assassin in (my way) - now if that is possible is the question -

Question is: With the perk on Illusion where you make all spells in all schools silent + perhaps dual wield casting attack with a Frost spell for instance.. when the target is in bed.. sleeping.. could that possible lead to a quick kill like with a dagger? Or bow?

I don't believe you can make Destruction spells silent. As far as I know the only silent weapons are daggers and bows.

invisibility or sneak with bound weaps now go my son!

In illusion or alteration there is a perk that makes your spells completely silent so you can sneak around and not alert people when you charge up your spell.

Edit: I'm sorry I didn't see your actual question, no spells do not get sneak attack modifiers.