Would this fan work?

It will work. But from the pics it's clearly 3 pin 3 wire fan. Just use 2 of them with standard MDD 2 pin connector.
One question: are you sure that your 1.25 DP has stock 120 mm fan?
IIRC 108 CFM one (Papst) was used in SP and lower clocked DP (867 and maybe 1.0 - not sure here). 1.25 DP should have 149 CFM Delta AFB1212VHE or SHE. All my 1.42 DPs have SHE IIRC.

 

On japamac's site parameters are more general than specific. Few dozens MDDs passed through my hands, and I can say with certainty that they had different main fans, depending on CPU speed and count. IIRC 1.25 DP should have about 150 CFM fan.
I'd say 92 CFM won't be enough for 1.25 DP on full load, especially if it's 2MB L3 one. NAP helps, but mostly when idle.
On the other hand, fans are software controlled, unlike in previous PMs. There is a kext in OS X with fan speed values corresponding to CPU thermal sensor reads. You can edit this kext according to new thermal management.

 

I once got the specs from here, but it is a single 1,25GHz, too. http://aquamac.proboards.com/index.cgi?action=display&board=talk&thread=1174&page=1#8403

Interesting to know that the Duals have other fans!

Does one of you know, how the MDD measures the temperatures?

 

It reads thermal sensor on CPU daughtercard. It's small 5-leg, rectangle chip placed between cache chips on CPUs side. On 1.42 DP card I have in the hand now it's marked U18 (on PCB).

 

Helpful as always, you are!