You may have to change the brake pedal. I posted photos of a 64 vs 74 pedal assembly a few weeks ago (search) and the later goes on the opposite side of the column, maybe because the collapsible column is thicker. I would like to get rid of the 74 pedal, so if you need it PM me. Real cheap $10 + shipping.
I am keeping the original columns in my 64 & 64 cars. I think it unlikely that the K-frame and steering box could be pushed back into the cabin. I suspect the concern was un-belted drivers getting impaled on the column, and I always belt up. I don't know if I would even trust an old collapsible column collapsing like it should w/ rust and such. I put Sebring seats in my 65 Dart. That gives an integral shoulder belt.
Don't believe everything people state about safety. The video of the Malibu slicing thru the old Bel Air looks bogus to many, including me and I am a mechanical engineer. The video implies that the new car is sturdier and more rigid and thus slices right thru the weak old car. This is the exact opposite of the "crumple zones" idea of modern safety. You see a rust cloud rise from the old car. Maybe the frame members were cut too, like in a Hollywood flick. There is a reason that people use my 65 Newport in collision derbies. How do you think a newer Malibu would fare there?
A lot of strange claims about brakes. If the brakes can lock up the tires, you can't get any more braking than that (actually pumping the brakes to stay just before lockup is ideal). A recent Wheeler Dealers episode showed them braking a WRX on a wet track after upgrading to big brakes. They commented on how much better it braked. Does that mean the original brakes couldn't have skidded the tires? The whole purpose of disk brakes is quicker cooling for repeated stops or from very high speeds. Doesn't sound like your daughter will be driving that fast. I suspect most problems with drum brakes is due to poor maintenance. I did put a dual reservoir MC on all my 60's cars, using a 95 Breeze ABS MC w/ 2-4 bolt adapter.