I want to make Nigirizushi with a fish similar to Escolar (also called Butter Fish), but prefer not to use that fish.
Are there other fish with a similar taste and texture?
Escolar is not butterfish. It is considered to be more closely related to the Oilfish species.
Butterfishes are from the family Stromateidae, which does not include Escolar.
As far as I know, there are no digestive issues reported with butterfish. That "wax ester" is highly localized to Escolar and Oilfish. So if you're looking for a "substitute", just use actual butterfish. Source it from somewhere you trust, or look for a more specific label like Pomfret or Harvestfish.
The wiki article had some helpful information. In answer to your question, the article included the following quote, "Escolar has been mislabeled or otherwise confused with the following fish: Atlantic cod, oilfish (related to escolar but in a different genus), rudderfish, blue cod, black cod, king tuna, grouper, orange roughy, sea bass, gemfish, Chilean sea bass, albacore tuna, and white tuna."
The wiki article, which includes more information that you might find of interest based on your question prior to edit, can be found here: http://en.wikipedia.org/wiki/Escolar