"Owen, dych chi wedi codi?"
Translation:Owen, have you got up?
Probably not - it was just meant as an example which I would consider calling for a familiar mode of address but which at least some Welsh people consider as calling for a polite mode of address.
The Edwin and Megan example was one of (admittedly older) people calling each other by first name + chi.
Basically, it's not as simple as "first name = always ti" even if that may often be true.
I get your point and I agree there could be situation when using "chi" and the first name concurrently is warranted. However, I was wondering if the duolingo course based as it is on English was not overemphasizing "chi" at the expense of "ti" because this distinction does not exist in English? I imagine it would be very tricky to construct English-to-Welsh exercises where you could reasonably expect both "ti" and "chi" back, meaningfully distinguished, no?