We do this pretty often in our Mondeo estate:
Big side of the split rear seat down, front wheels and saddles off, bars turned to the side, bikes go in upright, side by side, forks to the front.
plenty of room for everything else. taking pedals off makes it slightly easier to jiffle them in, but it might not save any time overall.
These are 100-120mm hartails. a strap/length of cord from the tie down point, up the hand grab on the roof, round the headtubes, back throught the grab and down helps them keep them steady for the comfort of the person in the back.
got 4 and 4 plus a long weekend’s food and luggage in, but that was slightly less comfy. Bearable for London – Brechfa, though. Specially for me, as I was in the driving seat! 🙂