Well with the thrust you are wrong. And the proof lies in the holding speed. Of course there would be thrust enough to maintain 240 knots, otherwise the FMC wouldn't display it as a holding speed. If I would fly that speed or not is another story, the point is that if flying e.g. .785, like in the pictures, I have plenty of time to react and increase thrust if the speed should decay for one reason or the other. Even if I had bad luck and it decayed to 240, I would still have enough thrust to pull me back.
This goes for this particular instance, other instances may be thrust limited (like maybe with a standard + 15 degs temperature, in the case of the pics it was pretty close to standard).
I don't fly with 40 degs bank at high altitude, max 15 degs as
pr. Boeing recommendation. I am sure you have a copy of the FCTM too, so there is really no point for me to quote what the flaps up amber band means, when you can have a look yourself.