I think Hickson has to start at this stage. I just don't see the Varejao/Shaq combination + 48 minutes of slow footed defensive centers working out well enough for the Cavs.
A Shaquille O'Neal and Anderson Varejao one-two punch at center gives the Cavs far more flexibility defensively in matching up against different types of teams. Against squads who have bigs who like to step out, against teams who run a lot of pick and rolls, and/or against teams who push the tempo.
Ilgauskas and Shaq can't play alongside one another either so that leaves Hickson or LeBron as the only viable options. Going with Hickson over LeBron, while trading Big Z, doesn't change anything in the end game. If it works out Hickson is the starting PF and LeBron is the fourth big. If it doesn't, then LeBron is the starter and Hickson is the fourth big in the rotation. In either scenario the Cavs will need another quality wing player to take the load off Bron while at the PF while adding some additional talent to the side.
Personally, I think Hickson will work out well enough to start him. His jump shot looked very smooth during the preseason games I saw him play and I think with regular minutes as a starter you'll see that consistently as the season goes on. But, even if it doesn't, I don't think that changes the plan for Cleveland.
I just don't see the chemistry developing for the Cavs while playing 48 minutes of Shaq + Ilgauskas + another 30 minutes of Varejao. And on top of that, having all the offensive problems which they clearly still have. They need more quickness, mobility, shooting and another quality perimeter player who can make plays.