Where are you getting the idea that Guy Fawkes had anything at all to do with republicanism?
There was nothing republican about the theocratic Roman Catholic powers backing him up, and while he was indeed a rather insignificant cog in the wheel, he was not working for any republican cause.
There was indeed a form of republican government in England some time after Fawkes:
http://en.wikipedia.org/wiki/Oliver_CromwellAfter the execution of the King <in January 1649>, a republic was declared, known as the Commonwealth of England. The Rump Parliament exercised both executive and legislative powers, with a smaller Council of State also having some executive functions.
The framework was nonetheless religious; although the republican combattants were different again from the ones Fawkes was trying to bring down, they shared Fawkes's targets' opposition to a Roman Catholic theocracy:
Cromwell's hostility to the Irish was religious as well as political. He was passionately opposed to the Roman Catholic Church, which he saw as denying the primacy of the Bible in favour of papal and clerical authority, and which he blamed for tyranny and persecution of Protestants in Europe.
-- not some philosophical republican opposition to monarchy.
And it was all a raging success in Ireland, say:
In the wake of the Commonwealth's conquest, the public practice of Catholicism was banned and Catholic priests were executed when captured. In addition, roughly 12,000 Irish people were sold into slavery under the Commonwealth. All Catholic-owned land was confiscated in the Act for the Settlement of Ireland 1652 and given to Scottish and English settlers, the Parliament's financial creditors and Parliamentary soldiers. The remaining Catholic landowners were allocated poorer land in the province of Connacht. Under the Commonwealth, Catholic landownership dropped from 60% of the total to just 8%.
On the other hand:
As Lord Protector, Cromwell was aware of the contribution the Jewish community made to the economic success of Holland, now England's leading commercial rival. It was this—allied to Cromwell’s toleration of the right to private worship of those who fell outside evangelical puritanism—that led to his encouraging Jews to return to England in 1657, over 350 years after their banishment by Edward I, in the hope that they would help speed up the recovery of the country after the disruption of the Civil Wars.
Jews were not parties to the politico-religious struggle going on for control of Europe and Britain.
So really, there just was no "politics of republicanism" in issue in Guy Fawkes' case. There were people with grievances, their grievances being the result of the politico-religious power struggle more than the cause of it.
Guy Fawkes's plan had more in common with the attack on the world trade towers, in the modern context, than anything else.