Just to declare, I am not a pilot but I do have probably 100 hrs in 737-800 fixed base simulators and I am pretty familiar with checklists and also the flows for each stage. I don't have any time on a320 series but I have checked a320 checklists as well to see what they state.

Having said all that, extending flaps is something which is usually done after pushback and engine start, and it is in my flows at that stage. However, there is no requirement for it to be done at that stage, and as you say they may not have been done due to the expected de-icing. The flaps check is in the before takeoff checklist though.

Anyway, based on what you have written I wouldn't be too worried. Things don't always happen at the same stage or in the same sequence for many reasons.