We have a Mk1 C-max with the twins, they are 15 months old and in the Tobi chairs now. Not sure about the new C-max but be careful about putting chairs in it, especially baby seats, between the moving rear seats and the false floor in the rear the only baby/base combo that worked was the most expensive thing on the market, the cabrio-fix maxi cozy thing. which we have a pair of for sale btw if anyone is interested.
We can get the easywalker duo pushchair in the boot, but then not much else. We have a topbox for big trips. It has been OK but personally in hindsight I would have gone for something bigger. Especially with the dogs, bike, bike gear etc.
The integraged blinds in the rear are good though, as is the mirror above the rearview that looks at the rear seats. also being able to completely remove the middle seat means we can actually get the pushchair in that space if you need the boot.