It’s an excellent question, Timothy. I don’t think anyone really needs them other than as an indicator that the objects are really bleeding past the crop marks and far enough out.

That said, a lot of printers don’t want ANY marks anymore. Most printers I’ve worked with in recent years say “don’t add trim/crop or bleed marks; our system does that for us.” It’s worth asking the printer.

Ah! Transparency Blend Space. I understand now. I don’t know of any way to change that across multiple documents, though I’m sure a script could be written to do it. (But for just 40 files, it’d be faster to just do it manually.)

Does it matter if you change this? Not necessarily. Though if you’re exporting to RGB then ID will probably complain that it’s in the wrong blending space each time you export.

More here:

My Grayscale Images and Colors Changed Suddenly

Not sure how well it would work, but you might try one of these:

Replace text with image, where text = image name?

or

Swapping Text and Images with a Free Script

I don’t know of anything specifically… not sure, but I wonder if this would help?

A Script for Setting InDesign Preferences