DC is a synthesis tool (that convert RTL code into gate-level netlist and optimize it). It may works with WLM and with TLUplus files. The using WLM mode is an old approach to synthesis. In this mode, DC does not know abour floorplan, about real wires, so the output optimized netlist may not be suitable for PnR tool. But, when DC uses TLUplus files (for RC estimation) (you need DC topographical license for it), it works with floorplan, it do some kind of real placement (and even some kind of routing - DC graphical license), so the output netlist is optimal as input for PnR tool (for ICC).
PC is an old tool and as far as I know, Synopsys does not support it anymore.
ICC is a PnR tool, and it works well in conjunction with DC.