But I don't have a clue if God draws the same boundaries as I would.
It doesn't matter. If boundaries exist, then we could find them. Phylogenetic analysis would have found them if morphological analysis did not.
No, I don't think any creatures that truly fly could possibly be re-purposed lizards.
You can think what you like, but the evidence refutes what you think. Birds are an excellent series of examples of
exaptation. That is where a trait evolves for one purpose but then has a totally different purpose.
Feathers are modified scales. In fact, scales can be turned into feathers by the timing of expression of BMP:
5. Zou H, Niswander L , Requirement for BMP signaling in interdigital apoptosisand scale formation. Science 1996 May 3;272(5262):738-41 "Expressionof dnBMPR in chicken embryonic hind limbs greatly reduced interdigital apoptosis and resulted in webbed feet. In addition, scales were transformed into feathers."
Originally, feathers were used for attracting mates, as happens many times in modern birds. But, as the feather displays covered more and more of the body -- thus becoming more and more effective in attracting a mate -- the first exaptation happened: feathers are also good for insulation. Other research has shown that many dinosaurs, including theropods, were warm-blooded. Insulation was beneficial to smaller theropods.
Theropods were already bipedal predators, using their forelimbs to grasp prey. As feathers covered the forelimbs, they also had another use than insulation: "flapping" the forelimbs allow the animal to run up an inclined plane:
3. Kenneth P.Dial, Wing-Assisted Incline Running and the Evolution of Flight. Science, 299: 402-405, Jan 17, 2003.
The small theropods could run up slopes and trees to either catch prey or to escape larger predators. As the feathers get longer and denser, they enable the animal to run up even steeper slopes. Eventually they are so good that the animal can run up a 110 degree slope -- more than vertical. However, right
here is where the feathers also start to get the animal off the ground! Voila! Instant flight.
Another exaptation accounts for insect flight, but there it involves the ability of the modified gills (future wings) as heat exchangers.
On the other hand, I am open to what I see yet try not to impress my preconceptions onto fossils we find.
I'm somewhat skeptical about this. You see, historically people who were not tring to impress preconceptions onto fossils, most of whom were creationists, looked at the first fossils of Archeopteryx and realized that here was an intermediate between dinos and birds. Archie was among the first major example of an intermediate species for macroevolution. I doubt you view Archie that way, but instead I bet you go thru all kinds of mental gymnastics (a la Duane Gish) to deny that Archie is an intermediate.