Re: Probem in design?
For R7 and R8 :
The voltage on the resistor is VCC - two times the Vbe of a transisor - VceSat of T5 (or T6) = roughly 5-1.4-0.2 = 3.4V
You need enough current through these resistors to make all transistors saturate, so take the less of the HFE of the pnp and the npn (the pnp will be less normally).
Ibase = Icollecor/HFE = Voltage on R8 / R8. This is a good start point for R8. Take the real value at least two times smaller to ensure saturation of the bridge transisors.
The same procedure you follow for R9 and R5, R9 and R5 form a voltage divider, but the voltage on R5 will be always one Vbe+one Vcesat (approx 0.9V). So the base current for T5 is defined by ((Vin-0.9)/R9) - 0.9/R5 . R5 is introduced as a safety factor, it will work without, but if the output that is connected to this input has leakage current, the transistor T5 can start conducting...
If you do the calculations, and add the information about the transistors you will use, I can check the results if you want...