Quickly creating or editing objects. The main target would be editor extensions, image a snippet that expands to an object on tab for instance

Nickel looks like something akin to Nix (JSON with functions), whereas August's goal is to allow you to quickly write a snippet that expands to your target document (e.g. via an editor extension) like Emmet. You can think of August like a snippet or shortcut to typing (or editing) a document rather than its own configuration language

I heard that they've named it the "SwitchCube Advance SP 3DS"

Multiple, they don't have to accept input but they can like in the DuckDuckGo example. The idea is to set up easy to type commands you can execute quickly

I wouldn't consider Melody a new flavour of regex as it compiles to ECMAScript regular expressions.

I'd consider being more verbose than regular expressions as a great thing for what this project aims to do, regular expressions are very write optimized which is the wrong (IMO) tradeoff to make in a shared codebase (or even your personal code that's more than a few days old) where code is read much more often.