Nope: TCP will lead to the other passenger being sat next to the GCH but does not transfer luggage benefits, that and (normally) being rebooked together in terms of IRROPS only comes when pax are actually on the same booking. There will also not be any special protection from potential overbooking or downgrades, etc.

TCP is merely a manual note in bookings so there is no formal benefit and nothing will ever happen automatically. Agents will use it to waive seat fee to sit the passenger next to you, and at check in, agents might see the note when you go to the check in desk, but that's about it.