I'll just add that literally ANY of these skis being discussed are going to run rings around a Brahma 82 when it comes to grip and suitability in dealing with hard icy conditions. That part of meeting your goals is a given no matter what you pick.For me, the SC has much better grip on hard snow and ice than the Brahma 82's. Make sure you have a good 0.5/3 or 1/3 tune.
The Head Rebel e/i.Race are great skis which I enjoy, however I find the WRT to be a bit easier to ski, a bit more forgiving, and a touch smoother--but is that worth twice the cost?
Head nomenclature can be confusing; keep in mind that the Head Rebel e.Speed is more a pseudo GS/Beer League ski like a Laser GS, while the similarly named Head SuperShape e.Speed is more of a easy going, versatile sport carver like the SC.
While I like and own both, I find the Laser GS to be easier to use, offers greater versatility, is more forgiving, and is smoother than the Head Rebel e/i.Speed--again whether that is worth nearly double the cost is another story. Both the 18-19m radius Laser GS and the Rebel e/i.Speed are suitable for cruising on resort slopes and neither of them require the strength and skill necessary to effectively use a 20-30m Masters or FIS GS ski. However based on your comments, neither the Laser GS nor the Head Rebel e/i.Speed is likely what you are looking for.
Bottom line for what you state you need: If you want a versatile, forgiving, smooth and highly capable sport carver which works well on-piste all over the resort in a variety of conditions including ice, get an SC or Head SuperShape e/i.Speed (the Head SuperShape Magnum would also likely work, but I have no experience with them). If you want a more precise, but also more demanding ski that is somewhat less versatile, but offers a higher speed limit then go with the WRT or Head e/i.Race.
What isn't always apparent without skiing skis back-to-back in the same conditions is how they vary in torsional stiffness. I've found that there really is a sweet spot for me when the torsional stiffness is enough to hold well, but not so stiff that the ski becomes very "digital" (quite On/Off with no ability to easily handle changes in pressure and edge angles, i.e. more analog). The special skis are those that manage to be well matched to your weight and skills so that they become very intuitive to use.