Changing things now seems like a lot of work just to satisfy a few users' duck fetish ;).
Is "Feddit" infringing on Reddit's copyright? You could argue that only the trailing "dit" is from Reddit, and out of context that's not recognisable. The upvote/downvote stuff predates Reddit too. Not a lawyer and all that, but I think we'd be fine.
I think the arguments for simplifying Lemmy to just a site named Quackhouse.uk could also be made for Feddit.uk. Isn't it usually the communities that are the draw? When mentioning Reddit to non-Reddit people I normally talked about subreddits that they'd maybe be interested in rather than just Reddit as a concept. The same can work here.
I do like the Quackhouse name. What if the domain were used as a landing page for the open UK-based communities? That way you can tell your mate down the pub about Quackhouse.uk and they'll be able to find it, maybe also seeing the details for Matrix or a curated list of UK Mastodon instances. Would that be overload for new users?
If we move I'll happily move with it, and it would be better to move sooner before things get more established. It just seems it may be a lot of disruption when it may not be needed.
My understanding is that the Quackhouse plans were for a Worse Case Scenario. With Tom back around, new admins appointed, and with other improvements coming we're in the Best Case Scenario. It must be frustrating for people that have been working on new plans to not have them play out, but if you put up a safety net and nothing falls in you don't start lobbing things in just to justify it.
