No and no as far as I know. But why would you want multiple accounts? Just use one account and subscribe to all the communities that are on different instances. You can even create + comment on posts with your account even if you aren't part of the instance.

The only real thing that you will miss out on is if you want to create a community on a different instance. I think you can only create communities on your local instance (Unless you sign up for an instance that restricts that feature).

Not possible, but maybe in the future? The standard (ActivityPub) they use is the same, but each software has to create it's own features.

@AeonThoth No. The solution to that exists, and it's called DID (Decentralized Identifiers https://en.wikipedia.org/...), but for some strange reason, it's not used in the fediverse. Using the ID from one of the "traditional" providers (for example, Google or Facebook) still ties you to a corporation. The fediverse is a step in the good direction, but self-sovereign identity is a logical and inevitable step that it's still pending.

The pitch for federalization gives the misleading impression that the system provides a universal (or at least portable) account mechanism. It seems to be a common point of uncertainty with users taking a look at the emerging platform.

From a usability standpoint, the sign-in process ought to be able to tell when someone is trying to join from a non-local instance, and provide means to redirect or authenticate them appropriately. Maybe something in the style of "Sign in with Google," only simpler.

I think upcoming versions of Lemmy/Kbin are attempting to improve link behavior to make it less likely to unintentionally stray from your home instance.