Is the ESX Server also in 192.168.168.0? If yes, then all that is required is VLAN 10 (I might have used VLAN 168 instead. It is just a number.) to be a member of tagged trunk between EX3300 and EX4300 and also be member of tagged trunk between EX4300 and MX.
This is basic VLAN/tagging/trunking situation. If ESX is not in 192.168.168.0 than traffic needs to be routed someplace.