There could be something in that.
Wiki tells us that 'emmet' is usually said to mean 'ant' although the Cornish for ant is completely different. The 'ant' explanation hinges on the Cornish picking up an old English word for ant and then using it to describe outsiders
https://en.wikipedia.org/wiki/Emmet_%28Cornish%29
'It is commonly thought to be derived from the Cornish-language word for ant, being an analogy to the way in which both tourists and ants are often red in colour and appear to mill around. However the use of 'emmet' to mean ants is actually from the Cornish dialect of English and is derived from the Old English word æmete from which the modern English word ant, is also derived (compare Modern German Ameise [ant]). The Cornish word for ant is actually moryonenn (pl. moryon) [1][2][3]'
I can't really see the Cornish describing themselves as ants however hard they were working.
There are plenty of examples in English for the final 'n' attaching itself to a noun and can be seen in Gaelic as well where 'nathair' means snake. Connected with adder or nadder.