Shoes

So we've figured out what everyone standing in the wedding will wear but I'm undecided about shoes. We were going to do converse but I'm on a tight budget and that was about $500. So looking for some suggestions.

We're getting married in August, in Texas so it's gonna be really hot. And it's an outside wedding. I have my sister and daughter as bridesmaids. My other daughter as a flower girl. They will all be wearing plum dresses and looking for knee high length. Then my son will be the ring bearer and he'll be wearing gray shorts, white shirt, plum vest, and my fiance's boys will be wearing the same minus the vest but plum suspenders and bowtie. My fiance is wearing a plum suit.

I plan on going with white dress and plum shoes. But debating on getting sandals now. Or maybe flats or toms. We're going to be outside on grass and dirt so I don't want heels. And if I do sandals for everyone what about my fiance? Sandals with a suit? Any ideas?