The frame will be fine based on your description. However your nomenclature and the year contradict each other. In 1986 there was no "CAAD" (did you mean 1996?). In fact I don't think 3.0s existed yet, I think it was what we fondly called the "5.0" (not an official name). This was a super heavy duty frame, one that was capable of supporting 150 pounds or more on the rear dropouts *without* a wheel in the frame. You can tell if the seat stays are thick, oval (in the non-aero plane), and about the same size as the chainstays.
If you meant 1996 disregard the notes about CAAD stuff. You can compare your bike to the catalogs listed here:
http://www.vintagecannondale.com/catalog.html
They are in pdf format.
I imagine you'd have pointed out any cracks, corrosion, or damaged tubes in your description if they existed.
Regarding 2.8s and 3.0s - for the era, they were fine. I raced a 2.8 and a 3.0 frame until either I crashed them enough times that the frame no longer tracked straight (2.8 - with dents or gouges in every tube except the head tube after 4 crashes one season) or until I upgraded out of the frame (3.0, which I still have). The only problems with them were typically cracks after massive miles or the fact that the tubes were bowed in the heat treating process. Since I cracked a Specialized M2 S-Works frame ("metal matrix", allegedly stronger than standard aluminum) and an aluminum Giant TCR frame, yet I never cracked a Cannondale frame, I can only talk about Cannondale frames cracking as an observer, not as someone who experienced it.
I think that worrying about the rider would be the most important thing. Agonizing over component decisions won't be very productive if you're not riding regularly in a group situation. You don't mention having other bikes to ride but if you have them, I'd race on that if they're appropriate for racing. Getting used to the bike/frame is probably the best thing you can do - in other words, build the bike with whatever, get on the thing, and ride.
As far as components go, I can guarantee you that you won't notice the difference between Ultegra and DA, for example, especially if you're using a bar end shifter for the rear derailleur, at least not for 1500-2000 miles. Front derailleur I think a steel cage derailleur is better than AL or Ti or carbon caged derailleurs because you can tweak them, and with a DT shifter, brand doesn't matter. The biggest difference between the new groups is durability when dealing with wear. Crashing is pretty similar - if you wrecked one you'd probably have wrecked the other.
cdr