Word: Tacky Rich People/Trashy Wealthy People [closed]

A number of terms (all of which, I admit, are mentioned in the OP's question) may be on point. Interestingly the first three listed below are drawn from French:

parvenu: one that has recently or suddenly risen to an unaccustomed position of wealth or power and has not yet gained the prestige, dignity, or manner associated with it.

arriviste: one that is a new and uncertain arrival (as in social position or artistic endeavor)

nouveau riche: a person newly rich: PARVENU

vulgarian: a vulgar person, where vulgar may mean "lacking in cultivation, perception, or taste"

All definitions are from Merriam-Webster's Eleventh Collegiate Dictionary (2003).

The predominant characteristic of a parvenu/ariviste/nouveau riche/vulgarian may variously be described as a taste for ostentation, flashiness, gaudiness, or conspicuous consumption.

In British English, such a person would be referred to as a Chav.

The word is not a perfect fit for your requirements as it is applied, not just to someone with money, but also to someone who tries to give the appearance of having money.

A chav is always tacky and ostentatious. The word is always used in a derogatory sense.