1.) In 2634 the system housed Alexandria, a major installation for ConFleet. It's where most of the outer worlds fleet (I forget the exact number at the moment) was stationed. McAuliffe itself was also essentially a fortress world. It was thought to be impregnable because of its massive shielding system. It had six (?) massive fusion reactors buried in mountains that powered the shield system for Alexandria, the Skyhook, and the major military installations at the base of the tower (Johnston Island for example). A large amount of Confed military power was forward deployed here.
From the description in AS, Alexandria isn't major shipyard facility for new construction. It does however have the ability to dock most of ConFleet's carriers, battlewagons, cruisers, etc. The best way to think of it, is like the Pearl Harbor for Confed, a forward base with repair facilities, command buildings, spacefields, ground troops, etc.
Looking at the WCP map, it does offer jump lines leading into Sol Sector, however, there are several jumps required to reach Sol itself. I'm discounting the Scylla jump line from Enyo.
2.) When Thrakhath took the Hakaga fleet to Sol, Tolwyn stated he had two choices 1.) Thrakhath could penetrate Confed space and spread out to occupy systems or 2.) he could punch straight through to Sol and cause the fall of Terra. Thrakhath went for the knock out blow that his father had envisioned in 2634. Although we don't know the direct route Thrakhath took, most likely he bypassed McAuliffe in order to get to Sol and clean our clocks.
3.) Judging from the WCP map, it may have been a system that fell to the Kilrathi near the end of the war, much like Torgo/Ko'Bar Yagar. It's listed as McAuliffe/Vikyah. In False Colors, we learn that Torgo fell near the end of the war and that the treaty that ended the war (Treaty of Torgo or Treaty of Ko'bar Yagar depending on who you are speaking to) was signed there, which we also see at the end of WC3 with Tolwyn and Melek signing the treaty there.
