More observations on the TT bike vs the road bike.

The doner bike weighed 20 lbs with pedals and bottle cages. (not exceptionally light but at its price point, not heavy either.) The TT bike weighs 21.5 lbs. 800 grams of that is in the TT handlebarsetup and the frame is all aluminium without carbon stays. TT bikes are clearly not strong suited in climbing ability.

With you weight fully on the arm rests, you do not slide around on the saddle very much. It also seems remarkably comfortable for the arms and back (assuming that you can bend down like that). One muscle group that will need work is the neck as you have to bring your head up quite a bit more to see.

Leader makes a fine frame at this pricepoint, in fact its better than many that I have seen that cost more.

Cyclocross brake levers will work fine as poormans reverse tri levers, just remember that the smallest version with a 24mm clamp is necessary for most aero base bars and many of the clip on extensions are only 22.5mm