I own the Montbell you have on your list, I got a large and room for a fleece under and fairly long in both torso and sleeves. No experience with the other 2 items.
I have worn under a lightish windproof to make up for the cold spots on the baffles, and this added noticeable net warmth dispite a bit of squishing, but just remember such high-loft down jackets will squish to nothing under any weight and will be cold particularly down the sides of the shoulder straps., less so on the back and shoulders as the pack itself is providing some insulation if you have padded shoulder straps and padded pack, but typically not badded straps down the sides. Synthetics don't squish nearly as much (why down is good for packing away smaller than synth for same insulation).
So you will need something non-squishy under if backpack wearing and then you need temps overall fairly low.
I find standing/walking its warm but if I sit down the arch of my back and the widening of the hip area acts to squish the insulation away around the lower back, so it needs some thick insulated pants.
The hood, it is very large, it is hard to make it close to the head even with the cinches up tight, I'd say yes get the hood it will squish to nothing under a shell given half the chance but when in use will provide a lot of insulation for its weight.
Montbell, top quality, its not leaking feathers, unlike the Patagonia Down Sweater I own which has less fill of down.