Tristated output to two common Base transistor issue

[RussMartin]

Thanks for an excellent result! (And the photo!) And thanks for bearing with me . . . I'm doing this on paper, not on a breadboard. I don't know what your LEDs are, so I'm having to guess at the Vf (I'm using 1.6 V) and assuming an If of 20 mA.

If you please, try increasing both Rcl's each by the same amount until the LEDs just go out, then test high and low at Rb again.

I appreciate your concern about floating inputs, but we can deal with that next. (I have something in mind.)