Undergarment Advice

Hi! I’ve got my dress and my shoes and and have booked an educational consultation with my chosen alterations company. However, I don’t have any clue where to get the right undergarments, and I’m not really sure exactly what I’ll need. There seem to be a lot of options! My dress has a very low back, and there is also some illusion lace on the back and over the shoulders. I don’t need a lot of help from shapewear, but would like the smoothing effect on my “love handle” area. I like the idea of a corset bra, but haven’t had much luck in finding a low back model. I’m mildly concerned that getting high waisted panties may roll, as they won’t be going very high. Does anyone have any ideas? I’ve attached photos of my dress, but I don’t have any pictures of me in it yet.