Do you think this breakdown has any merit?
I don't think INFPs look warm on the outside, quite the contrary.
The others aren't that great. INFPs and INTPs can be reserved and unsocial when you first meet them.
Yes
xNFP's: Shy, sensitive, and moody normally. Can think well, but sometimes via projection, and can allow it to overwhelm them such that they become highly critical, which they later regret.
You could call INFPs shy, but not ENFPs.