Guidelines for selecting suffix when making an adjective out of a proper name (-esque, -ean, -ian,

Examples:

For (Michael) Jordan, we often see Jordanesque. Why? Perhaps because he is His Airness (and the -esque suffix is associated with fanciness)? Maybe also to avoid confusion with Jordanians?

Plato -> Platonic. Why? Do names ending with an "o" generally get the suffix "-nic"? If so what do we do with Michelangelo?

And here are some for which there does not seem to be consensus:

Tolstoy -> Tolstoyian? Tolstoyan? Toylstoyean? Something else? Any guidelines?

Schelling -> Schellingian? Schellingesque?

Is this just mostly arbitrary and a matter of convention?

I would never deny someone the right to assign their own adjective form out of a proper noun that they own, or are assigned. I would argue that it comes from what appears or sounds best when spoken/read, but ultimately it would be like deciding upon a nickname or slang term. It is a proper noun after all, so it won't be listed in a dictionary text until it passes a certain popularity/consensus level.

As Edwin Ashworth has said, 'these things are influenced by what appears best'. But often there can be more than one such ending attaching to the same proper noun, the usage of each one having come to mean something different.

For example 'Platonic' is most often used in the sense of 'Platonic friends', meaning an intimate and affectionate relationship, but non-sexual. Their relationship was purely Platonic. It also implies being confined to words, theories or ideals, and not leading to practical action.

However 'Platonist' generally refers to someone who endorses the philosophy of Plato (which not everyone does, especially his views on government by aristocrats). Platonism can refer to revivals of Platonic doctrines, such as the 17th century 'Cambridge Platonism' which attempted to reconcile Christianity with humanism and science.

Meanings taken from digital version of The Oxford Dictionary of English (not same thing as OED)