Current mirror with multiple outputs
Is it possible to do the same with BJTs?

Yes it is.

But it is advisable to a resistor in series with the emitter of each transistor so that any difference between transistors (including temperature) is somewhat compensated for. Like this:



You can just repeat Q2 + resistor to get multiple outputs, like in the NMOS schematic.

What value for Re (emitter resistors) ?

Use value that drops around 100 - 500 mV across the resistors. The actual amount of voltage drop is not critical.

You will often see NPN current mirrors without the emitter resistors, these will often be on chip and there the transistors are very well matched so resistors are not needed.