The Vgs threshold rating of a Mosfet is when it is barely turned on, it is almost turned off.
Since your controlling voltage is 5V then you must use Mosfets that turn on properly with a 5V gate voltage. They are called "logic-level" Mosfets.
Since your supply goes as high as 30V then you must use a circuit that limits the Vgs of the P-channel Mosfets to 10V like a 10V zener diode.
The NPN transistors with a resistor in series with the collector are absolutely needed to prevent the P-channel Mosfets from an over-voltage on their gate. The NPN transistors need a resistor in series with the base to limit the base current. The 1k value of the gate-source resistors on the P-channel Mosfets is much too low.