Ros, I agree with you that the current exclamation mark in a circle character probably isn't sending a reinforcing message on all of those status messages. The previous "i" in a circle suggested "information", but that only works in certain languages.
However, I generally worry that check marks aren't quite as much a universally understood symbol as those of us in the Anglophone portions of the world might think.
There's an interesting blog post about an attempt at "Finding a Universal Symbol for Yes for Web-Based Training Courses" which explains a few potential pitfalls in trying to find symbols that would work. There really isn't a good option, outside of a simple smiley (☺) for affirmation -- and in work contexts, that could be viewed as insufficiently "professional". (I'd probably avoid anything that is an actual emoji, since even a , or slightly smiling face, can take on different tones of meaning.)
In that author's assessment, "No" had a much simpler, universally acceptable answer: a "general prohibition sign", a.k.a. the "No symbol" ().
The cross-cultural ambiguity of the check mark (✓,✔) seems to be why the check mark is avoided in so many other "universal" symbol sets, e.g. the AIGA passenger/pedestrian symbols, accessibility symbols, GHS hazard pictograms, or the UN OCHA humanitarian icons.
Moreover, in the (anglophone dominated) tech world, the check mark has taken on a very different symbolic meaning: verified identity. (cf. Twitter, Instagram, and Facebook.) Given that these are profiles of persons, that might be a choice that causes confusion.
A more generally understood "warning sign" would be the triangle warning sign (⚠️), i.e. "a triangle with an exclamation mark inside, used as a warning or alert.". Used in many countries outside the Americas as a traffic sign and often an indicator light on vehicles.
So if different symbols are needed, I would probably advise:
- ☺: Success Smiley
- ⚠️ : Warning Triangle
- ⚠️ or : Failure: Warning or Prohibited Action