In French music, the hautbois seems to have persisted to the late 18th C., but it is hard to interpret the notes I find with recordings of music made with old instruments; the instrument was modified, but I find references in music of the 1790s. Did the French name persist among some musicians rather than the Italian? Use of original instruments for Baroque and older music again has become common since the mid-20th C.
Not much help with the date for a general changeover by musicians to the oboe.

No luck with 'sketches' in that stanza. One meaning was 'a drop, or small amount', but that doesn't help with that stanza- I can't make sense of it.