I'll be honest, I grew up a Mormon around Mormon weddings. In a Mormon wedding, the ceremony is very small (only adults in good standing in the Church can enter the temple and even then the biggest rooms can only hold 20 people) and the pre-parties and reception are as big as they want!
However, FI is not Mormon so we are just winging it. We were thinking about having a small wedding (30 people) on a beach in California and dinner and foregoing the big reception my mom wants us to have in Arizona (lots of things combining to make it difficult).
My mom is very disappointed she won't get a chance to celebrate the marriage of her oldest child with her friends (all of whom are my friends' parents) and my aunts, uncles, and cousins so I was wondering if it would be inappropriate to suggest my parents throw an engagement party (Mormons don't typically have this pre-party so I don't think she knows about it) when the majority of the people who will be invited won't be invited to the wedding. But those same people are all accustomed to the Mormon wedding.