“As a name of opprobrium applied to a grasping or extortionate person (whether Jewish or not) who drives hard bargains.” Often used as an offensive and derogatory word as so in the context. (OED)

The phrase is used as an exclamation of healths, or toasting to someone or something, with which by Sir Anthony does following Sir Timothy refrain from drinking his beverage. The Royal Duke of Albany refers to James II who was established in this position following the restoration of his brother Charles II to the English throne in 1660. (Encyclopædia Britannica)

Regarded as a piece of a horse-harness (OED).

To take fortune, also regarded as time, by the forelock means to sieze an opportunity. (Oxford Dictionaries)

The term “healths," refers to to an alcoholic beverage, the act of drinking, and the act of toasting while drinking. (OED)

The reference to 1641 refers to the absolute monarchy that stood against the Irish insurrection of Irish Catholics. The Irish fought for numerous reasons, but mainly to have the Roman Catholic Church restored to its pre-Reformation position against British Protestantism. (Encyclopædia Britannica)

A charter of English liberties granted under King John on June 15, 1215 which held the sovereign accountable to the rule of law and documented the liberties held by “free men.” A code of laws. (Encyclopædia Britannica)

“Absalom and Achitophel” was a highly anti-Catholic satirical poem written by John Dryder in 1681. The allusion is brought up as Wilding sets to find out what Sir Timothy thinks about him. References this poem, he jabs at Wilding’s character as if he’d have nothing to do with the writing of such a work he’d regard as great.<br> ( Encyclopædia Britannica) http://www.britannica.com/topic/Absalom-and-Achitophel