Can you put fittings on external insulation?

there are specific fittings for external insulation, you may get some from the company that applied the insulation.

You have drilled a hole so should now know what is on the outside of the insulation. You might be able to hang lightweight stuff like a video door bell on the external cladding/coating a carful look where you have removed a plug will tell you whats there along with how the drill went through the surface layer.

For something really light you can often just connect to the skin thats on the insulation. Sometimes that outer layer can be fairly solid but in your case its sounds like there isn't really anything there to get a grip on.

Yeah, but house numbers don't get yanked on. The holes in the OP look like they're for a wireless Nest doorbell, and the fittings work in such a way that you have to pull on it a bit to remove/reattach it for charging, and that's done every few weeks depending on how the doorbell is configured.

What did you do in the end OP? I'm looking to hang a wireless video doorbell on my external wrap. I'm thinking some sort of exterior adhesive might be the best bet. This sort of thing:

good catch.

I was just linking it as an example of the type of adhesive that I'm considering.