Extracting Middle Name/Initial when name fields look like First Mid Last

I've uncovered excellent text conversion formulas to extract both the first name and last name from an 800+ column of names that look like:
Davy J Jones
Marcus Welby
Anthony Lazy Denosso
Janis Joplin
Mark T Seager
Mary Jean Post
Some fields have middle names an/or initials, but not all. I cannot find a formula to extract the middle name and/or initial, that also will result in a blank field if there is no middle name/initial.

See attached test file....

Can anyone help?