Nice intercooler!
You did the right thing if you didn't paint the cooling section of the intercooler. Most paint will inhibit the cooling effect of radiators so I assume it would do the same thing for intercoolers. Where you put the A/C in relation to the intercooler depends on what is the most important to you, HP or A/C. The front mounted piece will have an effect on the mid mounted piece. The intercooler appears to be plenty big. If you size the A/C condensor as large as possible you shouldn't have a problem with either. A transmission cooler located in the front or in the radiator shouldn't effect much. Unless you have a loaded trailer the cooler doesn't do much. If you decide to put the transmission cooler some place besides the radiator area there is another option. The street rodders have started using transmission coolers that are extruded aluminum. They are tubes with a lot of internal and external fins. The better ones are dopuble pass. Transmission fluid enters and exits from the same end. They are frame rail mounted. The non anodized ones cool better. The anodizing does the same as the paint on radiators and reduces cooling effeciency. I have on on my street rod. The transmission is lightly loaded and I don't have a trans temp gauge, but it seems to work well.
As far as the fan goes, I hate electric fans. Most are a pain. Most aftermarket ones have poor temp switches. I prefer the clutch type mechanical setups. On when you need it, "almost" off when you don't. No temperature switches to fail. No wiring. No fuses to blow. No doubts when driving. No extra wiring for the A/C, since the fan must run when the A/C is on. A good fan shroud is a must in my opinion. Make the fan pull the air through the radiator, not around it. With a good shroud the whole radiator is used not just the circle of it in front of the fan.
Now I just have to get my truck on the road. (No it doesn't have a radiator, intercooler, A/C condensor, or fan installed yet, so this is just me thinkin' in print.)