“The most staunch old earth theologians...”
Hold your horses there, there are a great many of the “guided evolution” variety that believe in whatever just-so stories the secular scientists pronounce, with their only caveat being that they think there was some invisible hand guiding the process.
We can suppose this for sake of theory, but the “guidance” needed would have had to be excruciatingly particular. The result is almost equivalent. Almost, not exactly, because it would imply some “begots” in the account that would not otherwise be there. Also what we see does not behave like anything Darwinian, to say the least. The bigger the creature, the easier it is for a given genetic move to toss it into the ash heap of history; but our modern record shows an appearance of species that burgeons at the tree tops, not at the roots.