I think you should go back to basics,read once more and just see the definations of each of the term you have asked .Then you will have a better idea of the hierarchy .
Anyways i have no idea whether answering this question will help you clear the interview .
Based on my understanding, test plan is normally drafted in the design stage,after analyzing the BRD and SRS. In the development stage, we finalized the test plan and start writing test cases and test scripts. Hope this helps.
I just happen to have a lapse in my super busy project schedule (while a server is being fixed) to provide you with the detailed links. But why not try some searches here on this site as this question has been answered many times.
Please remember that we are all volunteers here and we are currently working (except for Peter [img]/images/graemlins/smile.gif[/img] ) and cannot always provide a timely answer.
Going out of your comfort zone requires failure. True genius is measured by your recovery.
Ive worked in number of companies and all has different strategy of planning and documenting test data.
My Experience is to Analyze BRD (my organization calls it PRD) and SRS then write Test Plan which needs to be checked by project manager to give thumb up, then write test design and from test design we write test cases.