My initial thought on the downstairs is to do the satin version of each wall color on the trim.

Would be lovely but then you're locked into painting everything, walls and trim, whenever it's time for a repaint/color change. Expensive option long-term. And the trim can handle only so many layers of paint; eventually it will lose sharpness of detail.

I find Chantilly lace to be too stark for the downstairs. What would you do?

Choose a different color of white. You'll know it's different and works better than Chantilly, unlikely anyone else will notice.

Since Chantilly Lace feels too stark for your downstairs, you’re definitely not alone — it has a very high Lightness (L=95.3) and super low Chroma (C=2.6), which makes it read quite sharp and clean. If your downstairs palette leans more into soft whites and beiges, I'd suggest looking at whites - like below - with just a touch more chroma or a shift in hue angle to add warmth without going creamy.