I would say that the airport will cope just about OK with the three additional aircraft. Any more than that I would suggest would require further extension.
The chap above mentions only one boarding pass scanner being open but that’s all I’ve ever experienced and my longest queue has still been far shorter than I experience at MAN to give one example. If the second one is open there certainly won’t be a problem.
I’ve only ever seen two x-rays open, there are another two sitting there so there’s some more capacity.
A couple of weeks ago there were quite a few spaces available, they might just about be OK on that front.
Capacity of cafes/bar in the am peak in particular may be a challenge but perhaps that could be mitigated by throwing in a mobile cart or two.
People also talk like all 12 or so aircraft will set off at the same time, in reality they are staggered so the impact is mitigated. Right now for example once the two early EZY, MAN and DUB board between about 6-6:25ish the place really quietens down. This will be the period in which things hot up for the couple of new 7:15ish FR departures.
Another mitigation is Stobart themselves shifting departures back assuming they maintain the current fleet, for example it looks as though the E195 07:30 departure is going back almost an hour from winter.