i think you are complicating too much. if all you need is just to drive
few LEDs from 12V source and original outputs are not strong enough
for that, just add two CMOS chips (hex buffers or inverters).
two HEX4049 chips, 10 LEDs and one 10x 470Ohm resistor array is
all you need. If you get LEDs in array as well total number of
components is 4 and price for whole thing is ca. $1-2.
i think you are complicating too much. if all you need is just to drive
few LEDs from 12V source and original outputs are not strong enough
for that, just add two CMOS chips (hex buffers or inverters).
two HEX4049 chips, 10 LEDs and one 10x 470Ohm resistor array is
all you need. If you get LEDs in array as well total number of
components is 4 and price for whole thing is ca. $1-2.
The problem with most (all?) CMOS buffers and inverters is that their source current capability is quite a bit less than their sink capability. Driving 25ma to GND may not be possible.