The answer is unlimited. When the case says it supports upto 11 fans, that's only the amount of hardmounts the case has, you can always put fans on the hdd cages, mounted to the psu, basically anywhere you can slap on a zip tie or 2 or some double sided tape.
That said, with pwm fans, there are 5 way splitters that use a molex connector for power and a fan header for signal, so using 2 headers you can easily run 10 fans from the motherboard itself. With 3pin analog fans, you'll need a fan controller to run more than 2 fans from a header with any speed control. As said, your options are pretty much unlimited, depending on your choice in fans and methods of control, if any.
For that case, 3x intakes and 3x exhaust is plenty for air cooled cpu, for clc I'd go with clc+1 or 2 fans exhaust, 2-3x intakes and 1 fan on the hdd cage blowing across the pump. None of the fans needs to be run at anything above 800-900 rpm. Makes a much quieter case.