[DTV]

My impression was that BBC News would have their own output 24/7 and then would simulcast Brekafast, 1/6/10 on the UK domestic feed only.

Pretty much. The UK version of the channel will opt for simulcasts of Breakfast, One, Six and Ten, as well for a visualisation of Nicky Campbell. Some releases have suggested that other network output will also be simulcast and the original plans are for certain other radio content to be visualised at a later date. The UK service will also opt to cover certain live UK news events (press conferences, speeches, etc.) and will supposedly have the ability to opt for UK breaking/developing news stories (though the extent to which this will happen has never been explained in any depth). It was also implied that during things such as general election campaigns additional UK opts will occur.

Which makes the decision to continue simulcasting Breakfast on the domestic version even harder to understand. I mean, now when they are supposed to become one channel, this was a unique chance to actually have proper news bulletins on the UK version in the early morning hours, something they never had. Same for national bulletins, why not just have the bulletin that's gonna air on the international version at those times?

I can really see this angle but I am really waiting for the final plans. If the UK-opt is to be rarely used and other UK news is lacklustre or badly mixed in, then I'd much rather they did go all in on the international news channel route and ditch the simulcasts. If the UK-opt is to be used regularly or even if the final plans include some permanent separated UK-only output, I can see the merits of continuity with the current set-up, at least for now.

The signed bulletin would be a very controversial loss.

Though, of course, no reason that the signed bulletin has to be a network bulletin. The 13:00 hour was signed before News 24 started taking the One.