Learn English – Proper placement of suffix while using the first name only

All existing English words having both -less and -ness endings are of the XXXlessness sort; there are none of the *XXXnessless variety.

For example:

affectlessness, agelessness, aimlessness, airlessness, artlessness, awelessness, baselessness, beardlessness, blamelessness, bonelessness, bootlessness, breathlessness, carelessness, causelessness, cheerlessness, childlessness, classlessness, colourlessness, comfortlessness, curelessness, dreamlessness, effortlessness, emotionlessness, endlessness, expressness, factlessness, faithlessness, faultlessness, fearlessness, gracelessness, groundlessness, guiltlessness, haplessness, harmlessness, heartlessness, heedlessness, helplessness, hopelessness, lawlessness, leglessness, lessness, listlessness, mannerlessness, mercilessness, needlessness, nervelessness, noiselessness, normlessness, presciencelessness, recklessness, regardlessness, relentlessness, remedilessness, remorselessness, restlessness, ruthlessness, senselessness, shamelessness, sightlessness, sinlessness, sleeplessness, songlessness, speechlessness, spiritlessness, spotlessness, tastelessness, thanklessness, thoughtlessness, uselessness, voicelessness, warlessness, watchlessness, worthlessness, wretchlessness.

I think that the correct answer to this is refer to your style guide, e.g., APA, MLA, IEEE, SPIE, etc. These should fully specify details like this, and you only sometimes get lucky and have a real human address specific concerns like this (viz., the APA link).

In contrast to what @bib suggests, the APA reference requires that you include a comma between the first name and the suffix:

Doe, John, Jr.

(Also please note that the gentleman's official name will have a comma in it: John Doe, Junior or John Doe, Jr..)