I don't know much at all about Israeli politics or parties, but I would probably vote for a generic center-left or centrist party that's also against any form of (further) settlements in Palestine. It also has to be free of the religious fundies.
Which parties would that include ?
Meretz would be the closest to what you're describing. Labor would probably work if you wanted to vote for a major party. Yesh Atid is vaguely centrist, for sure, and definitely secular, but seems to avoid talking about the Palestinian issue like the plague.
Meretz are not centrist, just left, so they wouldn't be as good a fit for Tenders requirements.
Meretz actually doesn't sound too bad either.
Considering there's no real Green Party (only on a low level) and the Hadash's too far to the left (probably naive and utopian with their policies), I'd either vote for Labor/Livni or Meretz.
Is there any chance for them to end up in a center-left coalition ? Or better, what would a Labor/Livni coalition most likely look like ?
PS: I always cringe when I read about the "Shas" party, because in Austrian-German it means "to fart".