You've made a good choice in identifying Mendel as an ISTp. I think you're right on the money. He has the "Bob Dole" look, which is characteristic of most ISTps.

But I could have said those same things about my own childhood in large part. I think the childhood experiences Jung describes are in no way different from those of most people. (absent the parental problems, of course)

Something that's been on my mind: Jung says he was shocked by a childhood dream in which God defectated on a church. Question: how did he know it was God who was doing the defecating...?