The Honda Fit has more head room (ceiling height with lower floor) so you can put in 2 bikes standing up with front wheels off. I have not tried putting them in the Corolla HB but don't think it would have the same amount of head room. My HB is to replace my Fit, comparing the 2, they each have their Pros and Cons. I mainly use my wagon now for the bikes.
To keep your car clean with minimum scratches, cover the entire area with tarp before putting your bike inside. Also helps if you wrap the whole rear bumper with the clear bra material.
I don't like hanging the bikes on bike racks as I like my bikes inside the car for security, aerodynamic, and high G corners.

See below link for the clamps I use to hold the bikes in place. I wonder if you can take both wheels off and use them to clamp both front and back? The back wheel clamps will require to be lifted to clear the derailers. Or if you can lower or take off the bike seats to get more clearance? You have to measure your bikes and the HB to see if that may work.May be both bikes with both wheels off, one face forward and the other face backwards? Something to check. Some people put the bikes in upside down, then you should also find ways to cover the ceiling (or the tires) to keep it clean.
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