From the press release
We have already announced that British Airways will re-start flights from Belfast to Heathrow
so I'd say that BA will return with their own metal into BHD. Willie Walsh was vocal about wanting to bring BA back to NI, even before the bmi deal was on the cards.
In my opinion, BA will basically replace the bmi BHD operation, perhaps with a small reduction in frequency. If they keep the EI codeshare in addition, I don't know. Hopefully very soon, we'll have flights into T5!!!