You probably want to put each input of the demux on Q1 and Q2.
1Kohm and 100uF is probably running pretty fast, you can try 10K
Some schematic drawing hints: VCC and +5V are probably the same in this circuit. Most of us like to see the VCC mostly the top of the schematic, with branches downward as necessary. If a signal goes several places, such as your VCC does, gather them together before running them to the top.
Also, there's a strong preference for GND to be at the bottom of the page.
If resistors, capacitors, ICs are labeled with references such as R1, R2, C1, C2, IC1, etc it is easier to point out things.
A circuit hint: You're probably not comfortable with negative logic, but the TTL circuits shown (and the mux you'll probably use) will have more strength driving the LEDs with a LOW against VCC rather than a HIGH to GND.
The LEDs presently need resistors in series to limit the current, as 5V is too much to be unlimited.