Image trace on multiple objects at once
Image Trace option should work on multiple objects at once.
Sure it should!
Meanwhile there is a free script you can use to trace all the images in a selection or just in a folder: https://github.com/creold/illustrator-scripts/blob/master/md/Item.md#batchtrace
As the description says, there is a bug in Illustrator that prevents it from correctly applying the color presets, which you can upvote for fixing here: https://illustrator.uservoice.com/forums/908050-illustrator-desktop-sdk-scripting-issues/suggestions/46741876-tracing-bugs-in-scripts