The ones in the front should be near the bottom - you can use one or two depending on how many disks you have there as these fans also keep the disks cool.
The one at the top rear should exhaust the hot air out of the case. Since your cooler will have two fans on it, one exhaust is fine and you may not even need it as one cooler fan blows onto the heatsink and the other draws hot air away from it towards the back of the case. Depending on how large your case is the exhaust and the cooler fans might end up quite close to each other - not a major issue if they are blowing the same way.
In summary what you suggest is fine