Can I substitute vanilla extract for vanilla paste?

Agreed. And if you want a longer answer this is a good read:

http://www.realbakingwithrose.com/2006/08/roses_vanilla_bible_for_food_a.html

The short answer is YES! just used both yesterday while making French vanilla ice cream, and happened to notice the equivalents listed on the side of the Vanilla Paste jar said 1 tablespoon of paste = 1 tablespoon extract.