What I'd take:
Top layers:
Maybe 1 short sleeve wool shirt if you have one in case it's warm in Portugal.

A couple wool tank tops or camisoles

1 full zip wool layer or fleece layer.

At least 2 lightweight wool tops - icebreaker chakra or their 150 weight stuff.

Your ibex shaks or comparable 260-320 weight icebreaker.

If you need more warmth - bringing a vest along would be useful. A lot of the down ones fold in on themselves and don't use up a lot of space. You can sometimes get the kids north face nuptse vests pretty cheap and the kids large & x-large are actually quite big.

You seem to like jeans, so take your jeans.... They'll be fine for portugal and with your woolies or your sheebeast tights underneath them you'll probably be fine. But if you were putting your goretex pants over the jeans in boston, maybe you won't be.

1 pair of either goretex shell pants or some sort of softshell pants for skiing - You can probably do it in the ibex alpstars, but if you've already got the goretex shell pants, just stick with those. Softshell pants are more comfortable than goretex, they're warmer and you won't look as goofy just walking around town in them.

A couple pairs of ibex woolies (I dno't know how long your trip is and how many times you want to wear the same wool over and over - so if you don't want to change clothes to much - you can leave this off) or smartwool or icebreaker tights. If you had to, you could make them layer over each other for more warmth.

1 thicker pair of baselayers - your sheebeast tights if you want, or whatever

Wool hat of some sort.

A balaclava of some sort - I like the seirus windproof ones (this is for skiing)

Scarf

Gloves - I usually use a thin liner glove - there's the arc'teryx delegate ones that are wool, or patagonia capilene, and then a thicker layer over that (arc'teryx has nice fleecy ones and REI's got some nice midweight gloves), and then a goretex or waterproof shell over that. I also sometimes just use a softshell type glove with a shell over that. If you buy an insulated glove and bring it - if you need to adjust anything while skiing you get cold when you take them off. If you need brands or suggestions of these, let me know and I can go look.

Socks:
If you bring tall smartwool socks for skiing - remember those can also be used for layering when you're going around town in your jeans & woolies. I usually use a capilene liner sock under my ski socks. I don't like wearing more than that while skiing.

And you can decide on whatever other casual clothes you want.

It's going to depend somewhat on how windy it is and how you acclimatize to the temperature. I find after a few days skiing, I'm walking around town with my jacket & fleece completely unzipped because compared to the top of the mountain, it really doesn't feel all that cold.