I have a year old Vectra 1.9
I have a year old Vectra 1.9 CDTi Diesel and it does all those things, almost exactly as you describe. The only one I don’t know about is the coolant level, as I have never ventured under the bonnet, except the times to check the oil when the light came on (it’s a company car).
It seems to be cyclical, the oil light did that two or three times, and hasn’t done it since, and that is several months now. The brake light comes and goes. I like the car though despite all of that.