What is proper protocol on renewing wedding vows?

My son and his girlfriend were married last December and no one was invited to the wedding, although I suspect her parents were there. They moved to Atlanta my son lost his job due to the fact he had moving violations up here where he lived and lost his license, they were in Atlanta for 4 months. They came home and are now living with her parents. The 2 of them are 19 years old and are now planning to "renew" their vows. The two of them have "ALL" of the answers and smoking pot is one of them. They both work one at Subway and the other at Walmart. I have been asked to get a guest list together for their renewed vows. Need to add here when they were married they made at least 4,000.00 of which they don't have a penny left. I am reluctant to give a list for fear people will assume they are only looking for money. The wedding will be in a church and there will be "refreshments" served at another location ( a cash bar will be available). Is this proper or am I being to sensitive?