Leaving the beer on the yeast cake alone won't hurt it at reasonable cellar temps (think about bottle-conditioned beers).
The autolyzed yeast will also provide nutrients for the brett life cycle later on.
However, if you have a significant amount of trub, hop, or break material in the primary, go ahead and rack. A little bit is okay, but if you haven't done any filtering, I would leave it behind.
If you do rack - purge the conditioning vessel and siphon with CO2. With the drop in pH provided by the lacto, the sacch. probably wont be up for scavenging any oxygen.