Can any bones (but specifically Beef Shortribs) be used to make bone broth AFTER they've done a stint in the crockpot?

I'm not a bone expert, but I took the habit of making stock whenever I have bones left, whether it was chicken, beef or mutton so far, and I don't see why it wouldn't work with beef shortribs!

I have never heard of some kinds of bones being dangerous, or simply bad for stocks, but maybe just that some might be tastier than the others.

I watch a lot of French cooking shows and these guys make broth out of any type of bone you can imagine! More seriously, that's an interesting question and I can't find anywhere that some types of bones are bad, it seems that you can really use them all...

Let us know what the result will be!

Yes and no... You can certainly toss them in a pot and let it simmer for a few hours, you'll extract some flavor and there's no danger. But broth usually uses bones that have only been roasted, not cooked low and slow in liquid as I'm guessing you did in the crock pot. Depending on how long you cooked the previous dish, some or most of the flavor and even the gelatin could already have been extracted. Speaking of that previous dish, any spices used will most likely have imparted some flavor to the bones while cooking, which will then end up in the broth.

Personally, a lightly flavored Caribbean broth doesn't sound particularly appealing to me; I would just toss the bones. But there shouldn't be any danger to trying it if it does appeal to you.