While much more can always more to be said, I summarized a basic distinction between the housecarl and the thegn in 11th century, mainly based on A. Williams, before in: In the context of 11th century England, what was the difference between a thegn and a housecarl?

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According to her [Williams], thegn in the 11th century was basically a landowning aristocrat with at least full five hides of his own land for three generations (A. Williams, The World Before Domesday: The English Aristocracy, 900–1066, London: Continuum, 2008, p. 4.), though how large their estates varied within this social class (some thegns owned 25-55 hides in Domes day: Williams 2008: 5).

Williams also cites P. A. Clarke's English Nobility under Edward the Confessor (1994) for the episode of the powerful aristocrat's daughter who rejected the marriage proposal of not so wealthy/ powerful thegn/ nobility (nobiles) with "less than 40 hides" (Williams 2008: 4). Clarke lists the 90 most powerful thegns, probably with more than 40 hides possessions of land and sometimes called proceres ("chief men"), optimates ("best men"), or duguð ("elders"), but it is important for us here that: there must have been more than 90 of less powerful thegns who only owned a land of less than 40 hides in the 11th century.

Was there a Thegn for each village?

It is well-known that some (not all) thegns are commissioned to play a role in local government, and Simon Keynes's entry on thegn in Blackwell Encyclopaedia of ASE cites charter S1462 that records the law suit between Edwin and his mother in which three thegns are appointed by the single shire-meeting [of Herefordshire] to investigate the mother's claim. So, their presence was probably not so uncommon in the local society, I suppose.

As for more details on literature, please also check the reference list in the linked post.