Will this hbridge work?
As drawn, the H-bridge will not work.

You have N-channel MOSFETs for all components of the H-bridge.  This is OK if you drive them appropriately.  Imagine turning on Q1.  Initially, Vgs will be 12V, but as the voltage on the output of Q1 rises, then Vgs will become smaller and smaller... until Q1 is off.

Additionally, optocouplers aren't very fast, so your switching losses on your MOSFETs are going to be much higher than they needs to be.

There are chips designed for this exact application.  Have a look at the FAN7842MX for a good example. There are other designs, but this chip works great.  You will need one chip for each half-bridge.  There are full H-bridge drivers out there, I just haven't used them.

Enjoy, motors are fun!