Following up on this. Your suggestion worked perfectly. Lined up in my timeline with frame accuracy on top of my mix as hoped. 
The only issue that remains:
***Source files which are .MOV work great!
*** Source files which are .MP4 do not. The .MP4 files crash and will not even play in the preview window. This is the case for 2997i and 25i . All the filters and settings are the same. The only thing which differs is the container of the source. I tried an Avisynth workflow and same issue. I'm assuming it's a decode setting
Z
The only issue that remains:
***Source files which are .MOV work great!
*** Source files which are .MP4 do not. The .MP4 files crash and will not even play in the preview window. This is the case for 2997i and 25i . All the filters and settings are the same. The only thing which differs is the container of the source. I tried an Avisynth workflow and same issue. I'm assuming it's a decode setting
Z