I would have to say that I am not quite a literal Creationist, but I sympathize with both ends of this spectrum and want to see what might be in the gap between the two ends, that of intelligent agent intervention or design at some time in the past.
If Evolution has a quantitative theory, it would be a useful baseline to compare to observation.
Exobiology, if it find examples of life on other planets in our Solar System or inferred from observations of spectra of planets around other stars, can provide data points to compare to the Evolutionary model.
Panspermia, unintentional transport of life across interstellar space, or even directed dispersion of life forms, are all possibilities.
There are numerous quantitative theories associated with evolution.
If you start with evolution deniers who also deny the earth is more than 10,000 years old, you have all the mathematics and physics associated with radiometric dating.
On the subject of evolution itself you have various molecular clocks, none of which are perfectly constant, but which offer clues as to rates of change in populations.
There is the whole field of systematics, which allows the determination of the age of specimins (as in how old they were when they died) and where they fit in the nested hierarchy.
Before asserting that there have been interventions, it would be useful to state explicitly what you mean by intervention and how you would distinguish an intervention from a natural phenomenon.