Great topic to pursue. I will write more later but in my mind I think inmate " ideas" is a total nonstarter, and Dewitt was being sloppy when he used that reference.
My preferred explanation of what is innate is more on the order of pleasure and pain, extended to the innate ability to recognize relationships that then as we examine them are formed into ideas.
The best and even poetic presentation of such a position I have found is in the section from the work that Jackson Barwis wrote in the late 1700s against John Locke - the first of his "Dialogues on Innate Principles" found here: https://jacksonbarwis.com. (Specifically starting here: https://jacksonbarwis.com/DOIP-One/ )
In that work Barwis argues strongly against innate "ideas" but says that innate "principles" - such as feeling pleasure at the recognition of acts of benevolence - is a very different thing.
If I were forced to take a position on the direction Epicurus would likely have gone, that would be it.