If you are worried about strength then I would suggest to take the Dolce instead of the Dolce Elite. The extra carbon back would only make it weaker. There is allways great discussion if a carbon rear really adds something to a bike. Sure it looks better (tmho) but it doesn't bring any extra. Some bike manufactures even stopped making those combined frames since they experienced problems with them. I wouldn't worry to much the strength of the frame if you take a classic frame (without to much carbon added). The gear components are more likely to give in first, the can be very fragile when exposed to more weight or strnegth then they were designed for.

About the wheels, if you want strong wheels then you should get some hand build, classic woven, 36 spoke wheels. If you got a good LBS then he can make them for you. Brands like Mavic have some good quality rims (CPX33 are really strong). Often factory build wheels have weight limits on them (even the expensive once), the rule is often that should think about getting normal spoked wheels starting at a weight of about 200 pounds.

Personally I prefer the lever for shifting, especially when you get cold fingers or wear thick gloves. I have read stories that the tiagra group is significantly better then the sora group, but I can't tell if that is true from personal experience.