Maverick is the obvious choice, but since you want a derogatory connotation, how about

• wannabe-maverick, faux-maverick, pseudo-maverick, quasi-maverick, mom-can-i-be-a-maverick, maverick-in-vogue, fashionable maverick, trendy maverick, hipster maverick?

Oxymorons are always good for that — they can connote stupidity, and there's your derogatory sense.

It's not a word, but one funny saying comes to mind:

• That no one understands you doesn't make you an artist.

On Sycophancy

A non-regional term for a flatterer like you describe is a sycophant, which in my experience is often prefixed with either of two adjectives: either as a fawning sycophant or an obsequious sycophant, of which the fawning version is the more common — but perhaps less unctuous — of the two.

Compared with flatterer, sycophant is a “fancier” word, but that’s just because it comes from a classical language of antiquity (read: Latin, Greek, or as in this case, both) instead of a Germanic one.

It’s only a little fancy, though, not esoteric. Therefore sycophant would be recognized by (educated) native speakers of English the world around, as it is not a colloquialism or regionalism, nor slang.

Detail, details, details

But the plot thickens: it turns out that sycophant is one of those words that we don’t necessarily understand the ultimate origin of.

True, we know that it came from Latin sȳcophanta, a masculine noun of the first declension. Its Latin origin explains why it also appears in all the Romance tongues, like sycophante in French and sicofanta in Spanish, Portuguese, Catalan, and Italian, where it retains its original gender throughout.

The Romans in turn were just transliterating Latin’s sȳcophanta from the Greek σῡκοφάντης. Indeed, the word’s first appearance in English was from a translation of Plutarch, and there it was clearly transliterating from the Greek, since it was there spelled Sycophantes even in the translation.

But beyond that, things get murky, since the Greek means “someone who shows figs”, so a “shower of figs” or a “fig-shower” if you would.

But what in the world is a fig-shower, though? The OED2 notes:

The origin of the Gr. word, lit. = ‘fig-shower’, has not been satisfactorily accounted for. The explanation, long current, that it orig. meant an informer against the unlawful exportation of figs cannot be substantiated. It is possible that the term referred orig. to the gesture of ‘making a fig’ or had an obscene implication: cf. fig sb.² (See Boisacq Dict. Étym. de la langue grecque.)

The crowd-sourced Wiktionary in contrast pulls no punches regarding the putative obscene origin of the word:

First attested in 1537. From Latin sȳcophanta (“informer, trickster”), from Ancient Greek συκοφάντης (sukophántēs), itself from σῦκον (sûkon, “fig”) + φαίνω (phaínō, “I show, demonstrate”). The gesture of “showing the fig” was a vulgar one, which was made by sticking the thumb between two fingers, a display which vaguely resembles a fig, which is itself symbolic of a σῦκον (sûkon), which also meant vulva. The story behind this etymology is that politicians in ancient Greece steered clear of displaying that vulgar gesture, but urged their followers sub rosa to taunt their opponents by using it.