Look forward to making/sharing/tasting these. Have you tried these with non-dairy butter?

Since they have come a long ways since margarine first appeared in the stores- it's possible you might find one that would be acceptable. The only advice I'd have is to choose a version which comes in sticks, and is not labeled as a "spread". Spreads have less fat and more water than the stick variety does, which could leave you with a very large spread and one big cookie. Food 52 has an article where they evaluated them, and came up with a list they felt was the best of them. https://food52.com/blog/25097-best-vegan-butter-brands