You'd have to wire them in parallel otherwise voltage wouldn't be split equally.
If it were me I'd just put a splitter plug on the outlet of the timer, plug your lights in to one, then I'd wire up the fans like this using the fan controller listed at the top:
That way if one fan dies the rest still run fine, and all the fans will automatically be run at the same voltage. Should be easy enough to rig up.
Gotta be careful though, the top fan controller I linked has maximum current draw of 0.5A but the fans you have draw 0.3A each. You'd need to either find a meatier fan controller than can take over 1.2A or get a couple of controllers...
In fact the fan controller circuit looks like a very simple circuit... If I could remember my old systems and control classes I might be able to knock you up a circuit diagram for it. Alas I don't, but I am confident someone on these forums would know how to rig up a thermistor and power transistor to give you the desired effect... You could order the components and a breadboard on line and put it together yourself in a project box, use variable resistors to custom tune the temp range/fan speeds....
EDIT 3 (I'm on a roll!):
Alternatively (again) you could cancel/retuurn the fans you've bought already, and get some like this
, they have temp control circuits build directly into the fan and have an external temp probe. Would do away completely with the controller between the voltage converter and the fans. Auto adjusts fan speed over the range temp range 22*C - 42*C:
Fan Speed (RPM): 750 (22C) - 1500 (42C)
Just a thought, I'll stop editing my posts now....