These are things which haven't been tried on the two endings: ¤(Out of Commission) Failing the date once you've triggered Pegorino's marker, as well as at multiple points after reaching this point, WITHOUT loading the mission with the trainer ¤(A Revenger's Tragedy) Failing the date once you've triggered Pegorino's/Dimitri's marker, as well as at multiple points after reaching this point ¤(Wedding) Taking Kate and "date Kate" to the wedding marker, picking up Kate and then picking up "date Kate", picking up "date Kate" and then Kate, taking any other possible girlfriend to the wedding during both ending's weddings

I've tried the first ¤ after loading the mission through the trainer and failed the date at multiple points up until grabbing onto the helicopter, and it soft-locked every time. I'm assuming there'll be no difference if it's done without the trainer, but will still try. Also assuming there will be no difference if the same thing is done only with the deal ending (all fails occurred after reaching the shootout).

Have yet to try the date fail at the start of the actual deal mission (with Phil) WITHOUT loading the mission with the trainer, but will. It would have to somehow pass the mission early on, otherwise it won't be worth doing.

Here's two videos showing what happens if you fail the date just after the chase begins during each of the endings (spoiler: nothing useful was found) The setup for the deal ending is exactly like what happens in the other video, so it's not included (everything you see can be done without the trainer):