This is all explained in -:
Williamson, John, The elements of the military arrangemment,...... London 1982.
Allthough it predates the 1792 regulations it lays out what a regiment consists of which almost exactly matches the average complement of a standard infantry unit 1770-1807. Which includes there not being ensigns in the light and grenadier companies,
Places the corporals. States the circumstances under which the number of officers for a company gets to 4, and which rank is increased.
Its available in the British Library and maybe elsewhere.
There is not a bibliography in it and it does not explain the basis of the details in it, but those details do match what is found in Army lists and other documents.
[NB this is from memory - my notes are locked off in my laptop which I dont have with me right now]
The changes in officer complement from 1808 in the normal infantry and the light infantry batalions from 1805-ish partly follow the above explanation in becoming 4 per company due to having 100 or so men per comapny at full level, though there are also other changes with Majors and loss of the Capitain-Lieutenant appointment; for which I am not sure where these changes are notified and with any explanation as to why - I have a half suspicion the extra major is to cope with large battalions operating in two wings but hesitate to be firmer.