If you limited leave to remain in the UK (i.e.- not yet a British citizen), how can you or your children apply for OCI?
When you are granted British citizenship, you may then apply for OCI if you qualify. If you are eligible for OCI, then the children will also be eligible for OCI because for minors to be eligible only one parent needs to be eligible for OCI.
Your wife is not eligible for OCI as she holds (or, in the past, has held) Pakistani citizenship. So, in case you ever decide to return to India for good, with your Pakistani-British citizen wife, she will need to apply for an appropriate visa.
See also
FAQs.
regards