Wrong. The thickness of the insulation alone does not cause thermal bridging.

Right. If a thick insulation layer would make the basement too low, it cannot be installed. What might help in this case is vacuum insulation or combining insulation below and above the basement ceiling.

Right. Flanking insulation extends the insulation layer in the ceiling over the walls.

Wrong. A ventilation system does not help in defusing thermal bridges.

Wrong. This only increases the insulation thickness, but doesn't eliminate the risk of thermal bridging, e.g. at the junction with the basement wall.