There are no "special" restrictions
Capoeira attacks are modified by Dexterity, whereas Sumo attacks are modified by Strength, so in all likelihood you would be better at one than the other.
Aikido attacks are modified by Wisdom, so again, you can see that a character who was excellent at Aikido would not be nearly as good at Capoeira, unless he was an individual blessed with high ability scores.
Taking different styles does allow access to a wider range of maneuvers, which is its own reward in many ways.
Also, complimentary styles (two styles that grant proficiency in kicking for example) grant a one time competence bonus of +1 to hit.
So there are all sorts of benefits for cross training.
I tried to make the system balanced and fun first, realistic second, but within the suspension of disbelief range
Chuck