Reviving an old thread.
As a BA Gold I’ve just booked a Vueling flight with BA. While you can’t choose seats via BA, putting the PNR into the Vueling app allowed a choice of a good number of seats for free. The front 4 rows were chargeable, as were the exit rows. It also makes clear that It includes a 25Kg checked bag, and a 40x30x20 under seat cabin bag.