The article specifically stated that a second franchise arrangement would be announced for the Stobart Air operations for flights ex SEN and UK to Europe. So not Aer Lingus Regional branding for these services.
I'd agree that Darwin not British but I put it on the radar as it had a base in Cambridge and rumours mentioned of them operating to STN ...
Based on the feedback sounds like BE territory, though I cannot see EI being keen on any support of the Flybe brand given their previous encounters with the prospect of Flybe Ireland setting up etc. Re the Ryanair deal.
Cityjet brand would strike me as not being well known, and for those markets that it is known, would Cityjet want competition on its routes to other London airports?