pbs extension for dependent

Hi, I am planning to apply ilr tier 1 (5years) through post. My wife joined me in 2/14 hence her application would be tier 1 extension. Both of ours visa expire on the same day.

Through post, both the applications would be going to separate addresses.

1. Do I have to mention anything specific on her form?
2. Will HO start processing of her application at all or nothing will move until mine is decided?

1. All the necessary details that will enable HO to tag her extension application with your ILR application. If the form doesn't ask for any details about you / your application then this can either be done through the form (if there is space provided for additional information) or through a covering letter to be sent with documentary evidences.
2. I believe biometrics will be requested as normal but after that it'll sit in a pile until your own application is decided.