All of the items will be found out of doors within the Imperial City. All of the items have a distinct glow about them giving assistance in discovering their locations. They are very easy to locate in the evening and night hours.
Talos Plaza District; down the street from The Foaming Flask, in a garden near a well you'll find the Quilted Doublet.
Arcane University; in the yard, to the left as you enter, on the well you'll find the black hood.
(If using Open Cities Unique Districts you may have to enter the AI door to reach it)
Market District; directly in front of The Gilded Carafe you'll find the black robe.
Grand Filled Soul Gem (filled):
Elven Gardens District; in a laneway behind The King and Queen Tavern you'll find a filled Grand Soul Gem.
Market District; in front of The Feed Bag you'll find an apprentice retort.
Arboretum; behind a statue near the South Watch Tower you'll find the bog beacon.
Market District; in the laneway behind The Merchant Inn you'll find the Domica Redwort flower.
Arena District; directly beside the (new) Imperial Manor House (see side quest Ghost March) in a basket you'll find the mutton.
Bottle of Surille Brothers Best:
Talos Plaza District; around the fountain you'll find the Surille Brothers Best wine - vintage 399.
Copy of Tamrielic Lore:
Elven Gardens District; in the waterway near the door to Green Emperor Way you'll find a worn copy of Tamrielic Lore.