Pure Speculation Ahead of the Official Announcement

San Francisco Opera will announce the full cast of the 2018 Ring in September, or so I was told a while back. Herewith some unadulterated speculation.

Known, because David Gockley said so at a member event:

Conductor: Donald Runnicles
Wotan: Greer Grimsley
Brünnhilde: Evelyn Herlitzius

Likely, Because it's On His Web Site:

Loge: Stefan Margita (or if not, local fav William Burden, who sang the role in DC)

My Guesses, and That is What They Are; Nobody Has Told Me Anything; I Know Nothing, Jon Snow:

Alberich:  Gordon Hawkins or Eric Owens
Rheinmaidens: Your guess is as good as mine. Could be Adler Fellows, could be good local singers
Fricka: Elizabeth Bishop, who has sung the role in this production, or Jamie Barton, or Ekaterina Semenchuk, whom SFO seems to like
Freia: Melissa Citro
Donner: Christian Van Horn, because he's so good on Rattle's Rheingold
Froh: Brian Jagde
Fafner: Stephen Milling, because I can dream, even though he hasn't sung on the West Coast in more than ten years
Fasolt: Andrea Silvestrelli
Mime: David Cangelosi
Erda: Ronnita Miller

Sieglinde: Anja Kampe or Heidi Melton or maybe even Rachel Willis-Sorensen
Siegmund: Brandon Jovanovich or Brian Jagde or Stuart Skelton, unless there's a miracle and they've hired JK
Hunding: Stephen Milling or Andrea Silvestrelli
Valkyries: Generally a flock of Adler Fellows and singers from smaller roles in the Ring

Siegfried: Jay Hunter Morris and quite possibly an additional tenor
Forest Bird: Stacy Tappan

First Norn: Ronnita Miller (or the contralto singing Erda)
Second Norn: The mezzo singing Waltraute
Third Norn: Your guess is as good as mine
Waltraute: Jamie Barton or Elizabeth Bishop
Gunther: Christian Van Horn
Hagen: Andrea Silvestrelli or Stephen Milling
Gutrune: Melissa Citro