If the Blight card is <i>Aid from Lesser Spirits</i> and Bringer of Dreams and Nightmares is playing, is the Minor Power it gets subject to To Dream a Thousand Deaths?

If the Blight card is Aid from Lesser Spirits and Bringer of Dreams and Nightmares is playing, is the Minor Power it gets subject to To Dream a Thousand Deaths?

Yes. It says "as if played", so it obeys the Special Rules of the Spirit using it.
Thematically, the minor spirits are working through Bringer of Dreams & Nightmares - it's why the Power targets through Bringer's Presence and why Bringer gains the Elements from it. (An alternate version which could target anywhere but provided no Elements might be interesting.)