This particular sentence is admittedly pretentious and in an attempt to show off his or her sesquipedality the author you quote has run aground.
First of all, it should indeed be have since the verb in that sentence applies to three separate things: their vacuous posturing, their pharissaical sanctimonies and their sadducceical homilies.
I also don't quite get how something can have the tinge of becoming. It could have the tinge of but not really the tinge of becoming. At any rate, it sounds very strange to me.
In short, the whole sentence reads like someone showing off. Badly. However, there is absolutely nothing wrong with stringing multiple adjectives with similar meanings together. This has been used to great effect by many authors over the centuries. To take a bad example from a great author:
And with them scourge the bad revolting stars
(Shakespeare, Henry VI, part 1, Act 1, Scene 1 )
Though the sentence you posted is not really an example of it since the words are not so similar in meaning, the use of multiple words that mean the same thing (or which are unnecessary) is called pleonasm, a type of tautology. For example, this quote from Becket's Molloy which I found on Wikipedia (emphasis mine):
"Let me tell you this, when social workers offer you, free, gratis and for nothing, ..."