OK, @al1 found a major hicup in my design. The reverse diodes mess with my idea.The cool news is that the #DYPLED uses another style of multiplexing and is immune to the problem.
The bad news is that I have wasted some PCB surface.
But this is only a little setback. And if parallel wiring doesn't work, serial might !
I measured about 0.7V reverse voltage. There needs to be about 3.5V to turn one of the LEDs on. This might be possible...
It works !
At 3.3V, without limiting resistors, the luminosity is quite good, giving a bit of headroom for multiplexing.