Once upon a time there were Preachers who were not ordained priests, including a couple of women.
St. Augustine was the first non-Bishop to preach in the context of the Mass in Africa.
Context and liceity would be worth examining, if I cared much.
We had one at the Newman Centre where I was an undergrad. Liceity was not a big thing to most in the community. Looking back, it may very well not have been preaching at Mass because the matter was probably questionable, and if the matter is invalid, no Mass.