I am actually more interested in building the one and only god of multiclassing with 1 level in each class.
The dump stats for such build will most likely be Dexterity and Constitution. CON because you can start as a barbarian and have as much HP with 8 CON the rogue has with 14. Dexterity, because heavy armor is a thing.
I guess something like 12/8/8/14/16/16 after the floating bonuses apply.
Edit: Only if all the speculation about free multiclassing is true.
Not the worst survivability. What are you doing for damage?