It doesn't sound like you will be taking the output of any of your 3 receivers and sending it throughout your home; but have a receiver at each of the 3 TV locations.
Therefore, the simplest wiring may be to have the DPP44 in the closet, where it will use a single run to each of the 3 TV's. The 2 622's will each need a DPP Separater to use a single cable between the DPP44 and 622, otherwise each will require 2 cable runs from the switch.
Now, you will need upto 4 cables from the dish/LNBF to this closet. The outside location will depend on where the installer installs the dish or dishes to have a view of the southern sky (SE to SW).
A second option is to put the DPP44 outside, but make sure you have 4 RG6 cables going to the closet. You will only need 3, but if you add a fourth receiver in the future, then you will be glad this 4th cable is there. Actually, go with 5 cables, 4 for satellite and 1 for Cable TV/Broadband Internet.
Hopefully the house is not complete and an installer can go there, find the dish mount location, and run 4 cables to the closet or to the switch location which may not be where the current telephone & cable is.
NOTE: Total RG6 lengths upto 200 feet from LNBF to DPP-44 to Receivers should not be a problem.
OTA: Maybe it wouldn't hurt to have a cable ran from an antenna location outside, to the closet inside. However, this really should not be an issue since you can use a couple of diplexers to let the OTA RF signals ride on the same cable with the Satellite signals.