I’d been thinking about this and found this converstation - Obviously its been a while - but I’d like to drop some thoughts in.
I think the three ideas are each good. I’m probably more interested in the first - a guided setup.
I do get that there is real value in smoothing the introduction for new users as much as possible - I Know that means that there will be more, less informed or prepared users - but I really think that exploring home networking is something that should be enouraged.
I can see value in encouraging the setup of the admin password (the big alert on the LUCI screen when no password is not set is basically part of that) - I would think that it could go further and suggest/prompt/guide users through setting up a passkey to login, securing wifi as you suggest, maybe doing a ping to openwrt to check connectivity etc..
Assisting the setup of the WAN (and indeed it already sets up a basic LAN Interface so why not also help with that step - Obviously it might need to ask some questions (Country, ISP etc to be able to have a go at setting the right values if required (But then for a lot of hardware its simply plug the Wan interface into your ONT. )
My thought was that this guided setup doesn’t really even need to sit on the router - it could be an app or even webpage - since you would assume that connecting to the default Openwrt wifi or LAN interface would be available - and there would be steps before that in terms of flashing or installing hardware.
I could see some value in some modular template use cases that could be packaged together (Potentially just using some scripts - rather than particular visual steps - to implement some common use cases ) perhaps these could also assist with things like device key exchange with laptops and mobiles.