I've always made my Oberon clone with Munich, but you can try Vienna. Vienna will impart some malty sweetness, just not as much as Munich will.
Yes, I'd leave out the coriander and let the hops give you the citrus notes. If you can get Wyeast 1272, that is very similar to Bells. If you use it, ferment it warm, 73-74°F. If you end up going with US-05, then ferment mid-60s.