Doesn't have a single owner. It's a free software, build around a free-protocol. If at a moment, some developpers do not agree with Lemmy's main-dev, they're absolutely free to create a Memmy platform based on lemmy with their feature enabled. Just like at a point Libre office split from open office. Even better, Kbin/Mbin runs a fully different code-base and is still (fully) compatible with Lemmy. It's the magic of free software.
With instance I know, you don't give a commercial licence to re-use your content like you do on reddit. For example, Lemmy.world team cannot sell your comments to train an AI, or re-use the photo you post te sell T-shirt. On reddit (but also meta, tik tok and others) they'll do.
Have you noticed that you don't find these big GDPR cookies/tracker consent form ? Well, when you don't sell your user data to ads company, and don't put tons of trackers, GDPR compliance isn't complicated. Look at your instance privacy policy for LW it's there and compare it with reddit term of use it's crazy what we accept on reddit.
That said, please note that privacy friendly instances run because some people pay for it, if you like it, and can afford-it feel free to make a donation to your instances or the main developper.
At the moment it's a relatively small community, and you'll see the same nick-names everywhere, which means that in general the communities are nice and well behaved. There is a couple of instances which want to put politics everywhere and are annoying, but it's the exception not the norm.
Federation and fediverse works. From Lemmy, I've interacted with persons on Mastodon, have seen some of my Lemmy comments being retooted in Mastodon, have seen Mastodon/Firefish user posting on lemmy from their account there. And of course, you can exchange with people using lemmy on different instance.