simple

What advantages/disadvantages does it have over Lemmy?

It has more features, such as flairs, a way to move communities somewhere else, the ability to see comments from all crossposts, multi-communities, and it has a much faster development pace. The UX still needs some work, but that can be improved over time.

From a technical perspective it's made with Python which is much, much easier to use than Rust and attracts more contributors. From what I understand it's easier to host too.

Can I see and interact with PieFed instances and communities from a federated Lemmy instance? What about the other way around?

Yes and yes.

Is there a way for people to migrate an account from Lemmy to PieFed? What about the other way around?

You can export your Lemmy account settings and import them to Piefed, but not the other way around.

What android app options are available for PieFed?

https://interstellar.jwr.one/

The switch 2 has good specs by today's standards. Having anything higher than 1080p is a waste of time since there isn't any handheld that can run higher than that. The steam deck is 800p...

Not 'reportedly', people confirmed it doesn't work. it shows the games on your home screen but none of them launch. Also Nintendo can brick your system so don't even try using it.