Cheers!
The Lateiner edition has some slight alterations from Crawley. In the first sentence, instead of "catchword," it reads "propaganda." The Greek word is euprepes meaning something which looks good, but often with the implication of being specious, as in this case.
The oligarchs had claimed they were going to put the control of the state in the hands of the Five Thousand, "those such as were most able to serve the state in person and in purse." That presumably meant those who served as cavalry or infantry (hoplites). In fact, they limited the government to Four Hundred, and even that group seems to have been dominated by a handful of leaders, if you follow the rest of Thucydides' account.