Flashing LED's and use of switch
I suggest you consider starting again with a small microcontroller.







simulate this circuit &ndash; Schematic created using CircuitLab

To be honest, I'm not entirely sure what you want to achieve apart from flashing LEDs in multiple combinations where the specific combinations are one of a set controlled by a smaller number of switches. It doesn't matter, the above circuit will work, it's then just a matter of software.