OP - good find and I think might work well under the Scott jacket for one last layer. I like the bulit in neckwarmer as that is always an issue.
Heated gloves are a treat ...period tho Oxford heated grips work very well. The gloves easy to set up but the cabling through the jacket a tad annoying....well worth the warmth. The gloves are thin enough to go under most riding gloves.
Tip for feet ( I have the same issue with my Gaerne boots that are not insulated ) ....use chemical handwarmers tucked in the toes. One guy here even reuses his. - seems if kept sealed they can last for a couple of reuses.
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jeans and don't use body armour
Get some Thor or Fox knee armor,
I use these ....very quick to put on and provides on the joint coverage and are warm - come right down to my boots.
Cheap too - motocross boys have neat stuff.
I wear long thin wool socks under them all year round. You can still wear light riding pants and protect your knees.
But as a side effect they really keep knees and shins warm too,.
If you have skinny jeans then wear it over them and under the Rapala pants. ( kid sometimes just wears them outside his jeans....pair up with an armored shirt he be cyborg.