[1] For this usual meaning of e)rgola/bos as "contractor" (clearly from the noun e)/rgon and the verb lamba/nein), see e.g. Plato, Republic 373B; Plutarch, Pericles 31; and many epigraphical attestations. LSJ entry at web address 1.
[2] A trace of a usage of e)rgola/bos in a legal context, referring to advocates as 'contractors of lawsuits', occurs in Themistius, Orations 21.260b. What the Attic orators use with the Suda's meaning is actually the verb e)rgolabe/w, which also occurs most probably in the quotation (see note 5). LSJ entry at web address 2.
[3] Demosthenes, Letter 3 (Concerning the sons of Lycurgus) at ch.34 (web address 3).
[4] Reading h)/, from Demosthenes, for the Suda's e)k.
[5] The translation renders the Suda's text w(s; but a better reading is w(=n in, again, the direct transmission. Referring to taraxh\ kai\ dusme/neia, it implies a slightly different translation: "using them [= turmoil and malice] against you all, etc."
[6] A third instance of textual corruption in the quotation: the Suda's toi=s is actually tines in Demosthenes' text. The misreading of an abbreviation led a scribe to think of e)rgolabou=si as a dative plural participle governed by xrw/menoi, despite the presence of another dative. It is in fact a third person plural indicative, providing the main verb of the clause.
[7] For idioms like e)/rgon e)sti/, e)/. eu(rei=n, e)/. parasxei=n tini/ see LSJ at web address 4; and cf. generally epsilon 2909, epsilon 2911.
[8] An approximation of Polybius 8.3.3 -- perhaps via an epitome: the original is much longer, and does not contain the phrase 'had a hard time'. (Archimedes, surprisingly, does not have his own Suda entry [alpha 4113 is a homonym], but for this episode cf. under alpha 2797, epsilon 945, sigma 669.)