Any tips on how best to efficiently manage this connection:
US passport holder. No oneworld status.

Arr 22:05 LHR-MAD IB 3167 Terminal 4S (A340)
Dep 23:05 MAD-LIS IB 3118 Terminal 4

Reading previous posts I have a few questions:
1. Do I need to go thru immigration?
2. Do I need to go thru security re-entering Terminal 4 from the underground train?
3. Do they have agents meeting the flight to help us thru immigration and security?
4. Does IB hold flights since itʻs the last flight of the day?
5. Should I plan to miss my connection?

Thanks!