Few mango trees like to be kept that small (7 feet or less). Pruning a mango tree causes it to lose some of its nutrient and energy reserves (the leaves are a storehouse of micronutrients and wood stores carbs). It also incites a growth response. Neither is conducive to producing fruit.
Moreover, pruning also enhances fungal infection. I'm not entirely sure why, but my theory is that a) copper reserves are lowered and b) this combines with heavy vegetative flushing -- and leaves are most vulnerable to infection when they are not yet hardened.
A skilled tree magician might be able to pull it off. You'd need to take great pains to keep the tree well fed (but without nitrogen), to mitigate the growth response, and to keep fungal infection in check.
You might be successful keeping "dwarf" cultivars that small. Pickering and Julie would be candidates, for example. But carrie tends to be somewhat vigorous.
The one advantage of the carrie here is that, like many in the julie line, it doesn't require much in the way of stimulus to bloom.
So, I would plan on something more like 12 feet tall unless you're OK with an ornamental bush.