Revision 2 of the board is running as planned. I replaced the trusted level shifter buffer 74LVC4245A with a TI TXS0108, which is automatically bi-directional. The bi-dir feature is not needed here, but a good exercise for future use. Attention has to be paid, as there is also a TXB010x family which works better with fully driven signals. The TXS0108 is on order for open drain signals, e.g. the MISO sinal on SPI slave devices.
Channel 0 is on the RCA connector, channels 1,2,3 are on the VGA connector, accessible with a VGA to 3x RCA cable.