You need a manifold (full time) vacuum source to the modulator. The detent/kick down is not mandatory.
Use the outer vacuum port on the modulator. The inner smaller vacuum port closest to the case was used w/the EGR emissions system, so unless you are using an EGR valve, leave it alone. You can replace the two port modulator w/a one port type if you wanted to. IIRC the modulator you have is the push in type, not the threaded type but look first if you swap it out. The push in type has a clamp and bolt holding it in, real easy to see.
For the shift linkage, are you using a stock column shifter, or a floor mounted shifter? Is it aftermarket or stock?