(2) Answered by @garageshop. Hey wait, you cheated, you answered your own question!
(3) Likely this is some CSS within that 3rd-party stack that is interacting with the Alert stack and making it not visible. Is it visible in Preview Mode? When Published? If you wish to email me a few things I can look at it further, but I think this one just comes down to the stack you’re placing it into has some similar code that is hiding it in Edit Mode.
Yeah, the Alert stack works just fine in preview and published. I just have it placed in the middle of a long registration form to I have to drag to the top or bottom to be able to access it to edit the content. Indeed, for a while I could not figure out how it works since I originally used it for the first time in the massif of this long FromSnap form.
Would love to see a Foundry Alert Dialog by the way, owl be a great addition for doing TOS pop-ups etc.