My theory is far put but after a lot of thought it makes sense. But also can easily be disproven. What if by chance konahamarus dad was tobi
saruTOBI, it never shows him, we never find out what his moms meiden name is (could be uchiha but if not theory is easily disproven), he could be excluded from the uchiha clan because he is the son of the hokage, also he has black hair, old enough to fight against the fourth. Like i said it could make sense. If only I knew what the thirds wifes meiden name was!