When we refer to something suggestive of William Shakespeare’s works, why do we write Shakespearean (or, seldom, Shakespearian) rather than Shakespearesque? Why is an epic tale labeled Homeric rather than Homerian? What’s the difference between Christian and Christ-like? Is there a method to the madness of these suffixes?
The transformation of surnames into adjectives is fairly random, and writers are strongly advised to consult a dictionary or to research online usage rather than rely on common sense. When such a suffix has not yet been bestowed on a name, audition the four forms (-ean, -esque, -ian, and -ic) and select the most euphonious among them, but only after considering whether it’s wise to use any of the options at all, rather than to simply state that something is reminiscent of the works or beliefs of a particular person.
It takes a significant achievement or, more likely, set of achievements to merit this form, and your attempt to honor someone may be interpreted as irony. The good news, however, is that attaching one of these suffixes to a person’s name is, in a satirical context, an effective form of mockery or parody. (Consider, for example, a reference to a vocalist’s Bieberesque stylings. But beware of clumsy constructions like Kardashianian.)
In sincere usage, reserve -esque for the most deserving recipient names, as with Lincolnesque. The suffixes -ean and -ian — the former form dominates, though the choice often seems arbitrary — is suitable for most other references (Sartrean, Freudian). The -ic option is most suitable for classical (Platonic) or historical (Napoleonic) references.
And note the conversion of names ending in vowel sounds: Themes suggestive of George Bernard Shaw’s philosophy or the tone of his work, for example, are called Shavian, and a worldview akin to that of Henry David Thoreau is Thoreauvian.
The seemingly most sensible alternative — to simply append -like to a name — is rarely employed; the only widespread example that comes to mind is in the distinction between reference to Christian theology or values and to Christ-like behavior or appearance. (The suffix -like is usually attached to a root word without hyphenation, but an exception is made for proper nouns.)