Yes the psb will be pretty large by November, this could work but only if you gave a spacing of at least two feet between each psb because radicchios need good light and food, also your soil needs to be in top condition.
I have just planted a four foot bed with two rows of psb at 18in between plants, with a row of beetroot modules along the middle, making a third row along the bed (see This Month, it was after harvesting potatoes). Beetroot and fennel are good interplants for growing quickly.
For the Witloof I think you are better off planting them at 12-15in without an interplant as they quickly grow big.