If the existing J-pole is wall mounted, there may not be enough clearance to the rear for the 7694 or HBU-33. (Your description and measurements make me fairly certain that the existing wall mounted J-pole is not going to work with the typical Yagi style antenna.) A DB4E would be a much better option in such a case. However, there won't be room for the CS5 on the same J-pole. If you opt for the two antenna solution, they can be on the same mast, separated by at least 3'. They can also be mounted separately. I believe the CS5 ships with a UHF/VHF combiner so you'll be able to run one down-lead into the house.
Given the edge path conditions due to the obstructing terrain, we don't know if the wall mounted site is going to provide reliable reception. I would simply try the location that you prefer, if it works, great... If needed, move on to the next most preferred site, testing reception before committing to holes in the wall, eve or roof.
I would try the install with no preamp... Why spend money if it adds no value?
http://forum.tvfool.com/showthread.php?t=13646 If the need for amplification is proven, the 10G201 is a good option, as is the RCA TVPRAMP1R.