How to drive paralleled mosfets with a microcontroller?
I can't even guess what you think the four diodes in series with the FETs are doing.

There is little point to the 470 &Omega; gate resistors, especially with such a high value.

Yes, you can parallel MOSFETs, and you can use parallel drivers or drive them all from the same driver.  The gate of a MOSFET looks mostly like a capacitor to the rest of the circuit.  It therefore takes current to switch.  If the driver has to switch 4 together, it needs to provide 4x the current to switch them all in the same time.

Since you are switching very slowly, the total switch transition time isn't much of a issue.  You therefore don't need a super high current driving each base.

You didn't provide a link to the FET datasheet, so we don't know what the gate voltage needs to be.  However, since you're switching 240 V, I'll assume the gates need to be driven to 12 V or so.  A microcontroller can't do that directly.  There are many low side FET gate driver chips available that take a logic signal in and produce the gate voltage out.  One of these between the micro and the four gates wired together would do fine.

One problem will be producing the 12 V for the gate driver.  Some drivers will do this themselves, but rely on regular switching for the internal charge pump to work.  Some have free running oscillators to run their charge pumps, and can be held at fixed levels indefinitely.

You will probably be better off making the 12 V yourself.  The best strategy depends on what power voltages you already have available.  If you only have the 3.3 V that runs the micro, then a small boost converter that makes 12 V from the 3.3 V is probably the simplest.  This boost converter doesn't need to supply much current since you are switching so slowly.  It does need to have a decent size capacitor on its output to handle the sudden but short-lived current demand when the gates are being switched from low to high.