1. Your agent (authorised and registered)/Indian (Air India) may provide certifiace indicating the LTC80 fare for the sector and for THE DAY(s) of your travel.
2. Break ups for the sectors would definitely be provided by your travel agent. You are mentioning e-ticket by the airline. The invoice by your agent would show the break up.
3. You can claim as per your ACTUAL travel only and not on hypothetical basis. If you would not travel Delhi-Srinagar to and fro, the same can not be claimed. Travel expenses between Srinagar-Jammu by road would be reimbursed only if the transport between Srinagar-Jammu would be operated by Govt/PSU/Local Body etc and reimbursement will be subject to the entitled class of travel.
Hope this helped.