You really need to decide if you want the lighting to go above and beyond just what's required for this shoot. I shoot with Elinchrom gear - and it's good stuff, but they do make quite a few combinations of gear - many of which will be suitable for what you're planning, but they may not be suitable for other jobs that you may want top use them for (eg something more portable and battery powered like the quadra range) (that also has skyport receivers built in).
Most product shoots like this are pretty straight-forward; 2 lights - 2 softboxes - camera - appropriate lens - tripod. You mentioned the 600EX RT Flash - great flash (I have 5 of them), but not sure what you'd be planning to use that for in the context of the suit shoot??
Other than that, the only other thing I'd add would be colour profiling and calibration equipment if colour accuracy is required (eg spyder colorimeter and passport to profile camera and monitor).
If you shoot against a backdrop like you're planning it'll be gray not white if you're illuminating it with the same lights as the suits, but usually it's a moot point because it's usually easier to just extract the product in post-processing, so it doesn't make a lot of difference.
Last but not least, you'll need to post-process the shots correctly with regards (especially) to colour correction and sharpening.