So you are only doing the single fan and not a push and pull combination with these fans? What is your experience with the push and pull combination and quieter fans?
As I said, I built an enclosed case for the S5 to control airflow more - and in my tests with the case, doing push and pull had more effect on power consumption then temperature, so I ditched it. I also found that pull-only was better, as you didn't need the grill to protect the blades, and you don't have the issue of debris buildup on the front edge of the heat sinks.
If you're doing a 'naked' S5, then it does benefit from push and pull fans, because the airflow is really not all that good by the time it gets to the end of the case. Two Kaze's would be overkill, and two of the lesser fans were not sufficient in my tests - in this situation, I just used the Kaze in place of the stock fan, and while it doesn't perform as well (if I recall, it was maybe 5c hotter), it is much quieter than stock. But once again, this was before they put in the manual fan speed control, so you might be able to get near to the same performance without buying anything else, just manually setting the fan to 30% or less.
In terms of mix and match fans, I generally don't like that, so don't do it. Anytime I've used multiple fans, I've always used the same make/model.