Will Apple and Brie salad go with veggie lasagna?

I would say "yes." The apple will cut through the fat/cheese of the lasagna. But I would go easy on the Brie.

Here’s my two cents....
Crunchy, crispy iceberg lettuce, red onion, black olives, sliced pepperocini, Italian dressing. Many will balk at iceberg lettuce however I love the fact that it is high in water content, few calories, it doesn’t sit heavy and is refreshing. Perfect with lasagna IMO.

Assuming romaine is now ok (and I've seen it in the markets), I would opt for a classic Romaine salad with sharp tart/salty flavors, perhaps with cucumbers, mashed anchovies, lemon/olive oil dressing. Something Caesar salad-like, rather than sweet/fruity. But it's your call.

For winter bright salads and some vitamin c:
Maybe a cole slaw spiked with apples, carrots, onions, parsnips.
Or some wedges of roasted sweet potato with pomegranate seeds, juice or syrup in the dressing.

If the lasagna is cheesy, I'd opt for a bright, vinegary, just-greens salad (without anything creamy). But it's a totally personal call!