Should analogue multivibrator and comparator pullup circuit have separate supplies?
Usually you power everything in a circuit from the same supply voltage, unless you really need different voltages for different parts of the circuit. Since your circuit only needs 5 volts, you can of course power everything from a single 5V supply.

Think of it like a power bar: You can plug in as many devices as you want (as long as you don't overload it, of course).

Your circuit needs so little power that overloading your power supply is not a concern.