You are going to have a great time! I don't see how wearing bra and panties would be a problem, she should wear whatever makes her comfortable
My advice would be to allow your wife to progress down the road to public nakedness at her own pace, don't worry she will get there. My wife was a bit apprehensive (as 95% of women would be) about the vibe of the resort even though we are quite liberal. We have been to St. Maarten several times and topless sunbathing is the norm there so no surprises, but planned theme nights and the like are a bit intimidating. Within 2 hours of being at the pool on our first Temptations trip she was loving the atmosphere, day 2 she was topless and didn't look back. I cannot encourage enough the lingerie party as a great intro, that was our first night there and the no camera policy, along with not being allowed in without costume was great to put people at ease. Temptations is a fabulous place for women to embrace their bodies without feeling pressure to look like Kate Upton. Its about real women and men with real bodies having real fun!
Thanks for the advice. I do plan on letting her go at her own pace. I am pretty sure once she gets there things will go well. She is laid back but think she will open up once there.