You better use the circuit diagram in #8. The H-bridge circuit in #3 is too specialized and simplified, will work only under certain conditions. The weakest point is the restriction of the supply voltage, which is supposed to equal the logic HIGH voltage of the driving output pin, under load. Even then the top transistors may not turn fully on, due to the voltage drop in the base resistors. If a base current of only 1mA is required, this will drop 1-3V on the 1-3k base resistors, another 0.7V on B-E, and 0.4V on the C-E of the bottom transistors, so that less than 3V is left for the coil :-(
Increasing +V doesn't help, because the emitter voltage can not exceed the base voltage, which is determined by the connected controller output pin. In practice the top transistors should be PNP, with another NPN transistor driving their base.
The hollow arrows mean ground. The diodes let the back flush rush into the power source.