Hello, friend!
You can configure the same service VLAN for the two ONUs connected to the OLT and bind the two ONUs to a VLAN profile. Layer 2 communication can be enabled in the profile.
If the two ONUs connected to the OLT can communicate with each other, the PC can also communicate with each other.
You can select optical modules from other vendors. However, you are advised to use optical modules from the same vendor to ensure normal service operation and device compatibility.
Thanks!