If Moses killing the Egyptian followed immediately after Exodus 1:12 in J, then the source gave no introduction to who Moses was or his parents. (Baden 2012:74)
I expected an eminent professor's treatise "reviving the #DocumentaryHypothesis to persuade me, but it's having the opposite effect.
Aha, I see that Prof. Baden addressed the issue, only in an endnote. (I hate endnotes!) He says that introducing Moses with וַיְהִ֣י׀ בַּיָּמִ֣ים הָהֵ֗ם וַיִּגְדַּ֤ל מֹשֶׁה֙ וַיֵּצֵ֣א אֶל־אֶחָ֔יו ("And it happened in those days and Moses grew up") is like "That was the period in which Abraham Lincoln came of age." But is it?
I'm not aware of any other introduction in ancient Hebrew literature (even famous figures like David, Solomon, Abraham, Noah,
or Adam) that is so abrupt, except perhaps the references to David in Ruth 4:17, 22.
Contrast אז constructions in Gen 4:26; 13:7; Ex 4:26 (also J, according to Baden).
Baden argues ויהי בימים ההם cannot refer to Ex 2:1-10, because Moses was a little child. But the same phrase in Ex 2:23a (also J!) means "sometime later," as also in 2 Sam. 28:1 (the only other use, in Jud. 19:1, is unclear).
2/3
Baden says that J reading straight from Ex. 1:12->2:11 makes Moses "a common Israelite," but his reconstruction of J doesn't say that. We're not told who Moses's parents were! Maybe J's Moses wasn't an Israelite at all, for all we know from Baden's J!
OT Textual Criticism Amateur