this lecturer has been with the hiring department for over a decade
No way that person is getting the job. If there is an inside candidate, it is someone else.
Look, you are far down the path of making yourself crazy here, constructing elaborate scenarios based on some sliver of a sliver of evidence. The scenario that leaps to my mind is that they are afraid that the search will be cancelled and want to fill the position quickly, and perhaps also that they are afraid that a statewide travel ban (such as my state has right now) will mean they cannot interview at the MLA after all.
Take the interview that they want you to take and knock their socks off. Good luck.