Hmmm..
I can't see your spacer setup, but you wish to remove the spacers below your bars and put the Fred bar underneath, and then attach the Ortilieb bag to this?
This will, in effect, pull the Ortilieb bag back under your bars quite a bit as that Fred bar is quite short. Lowering it slightly might help with clearance. But you also have all those cables to deal with.
And access to your bar bag will mean removing the aero bars to open it up.
You could probably achieve a similar configuration by putting a second road stem below your bars, if you have the space, then adding a stub of a handlebar to the stem. This would allow you to adjust the location of your attachment point a bit with a longer or shorter stem, or different angles of stems.
There are also handlebar "Light Bars" which give you auxiliary mount points. Many of them are pretty flimsy, and only made for light stuff. However, this Nitto Lamp Holder looks a bit more solid, with 26.0 and 31.8 options (for the main bars). The stubs are still small, but something similar might work for an auxiliary mount point.
Where to mount my lights?
It would seem like someone would have already integrated a bar bag with TT bars (for Randonneurs?) But, I don't see it. Perhaps swing the bars wide for combined support and access to the bag, and even use the bag as part of the pads/rests.