Is two weeks enough time to fix a wonky bodice or should I buy a backup dress?

I rescued a bodice about a week out once, so I'll tell you what worked and what I'd skip. The zipper first. Stay tape absolutely works after the fact. Unpick just the zipper area, fuse a narrow strip of stay tape (or even lightweight fusible knit interfacing) on the wrong side along where the zipper sits, let it cool completley, then baste the zipper back in by hand before machine stitching. The tape stops the fabric from stretching while you sew, and honestly the hand-basting is what kills most of the wave even before you get to the machine. If the seamline itself has gone soft from being picked twice, the interfacing strip doubles as reinforcement there, so you get two fixes in one step.

Darts pulling wierd across the bust usally means the dart point sits too far out or the legs aren't even. Try the dress on inside out and pin the darts to where they actually want to sit, mark with chalk, then restitch. That's a couple of hours, not a redo. The side seams twisting is the one I'd probaly let go, because twisting usually means the panels were cut slightly off grain, and no amount of seam fixing sorts that out. Sometimes a good steam press with a clapper coaxes a mild twist flat enough that nobody sees it in photos. Worth trying before you pick anything else apart, since that fabric is telling you it's tired.

And yes, buy the backup dress. Not as a failure, as insurance. Every dressmaker I know has a backup plan for the thing they're wearing once in thier life. If your dress comes togather in time, the backup becomes the reception or after-party dress, or you wear it getting ready in the morning so the handmade one stays pristine for photos. The sunk cost feeling is real but it fades. Wearing a dress you made down the aisle, even a simpler version of what you imagined, doesn't.

Agreeing with the backup dress advice hard. I bought one two weeks before my own wedding after butchering a lace bodice, and it was the best money I spent that whole year. Funny thing was, having the backup in the closet killed the panic and I actually finished mine with a clear head. Nothing ruins your stitching like sewing while crying about deadlines. One thing I'd add about the tired fabric: don't press it til the new seams are in. I flattened mine out over and over trying to fix things and ended up with shiny marks that never came out. Press once, at the end, with a cloth over it.

Agreeing with the advice to leave the twisting side seams alone. I fought a twist on a lined jacket once and every time I unpicked and re-sewed, the fabric got more lopsided, not less. What actually helped was pressing the seam over a tailor's ham with steam, then letting it dry flat overnight before touching anything. The slack redistributed and the panels hung straighter by morning. Save your seam ripper for the darts and the zipper only.

Not a dressmaker, just someone who learned this the hard way with a curtain project that went sideways, but does the stay tape thing need a special iron or will a regular one work? I only ask because I tried fusing some stiffener onto fabric once and it glued itself to the iron plate and made a mess. Also, that idea about trying the dress on inside out to see where the darts want to sit is genuinely new to me, pinning things while wearing it seems fiddly but I guess that's how you acutally see the problem on your own body.

Update: took the plunge on the stay tape under the zipper like the first reply said, and wow, the waviness is basially gone. Regular iron worked fine too, no glue disasters. Still fighting the side seam twist though, tried the steam and ham trick overnight and it's better but not perfect. Is a slight remaining twist something the camera would even notice, or do I keep fussing?