I can really see it being Appleton/Shakespeare (or both) alongside Shan until end of season.
It's too risky to have a new manager coming in now and changing the way we play again. If we had brought someone in when DM was sacked, they could have kept Shan involved for Swansea and Brentford to get an understanding of the team, and used the international break to make slight tweaks in how we play.
The one thing the club need to ensure is that whatever happens, we keep Shan on in some capacity. Whether that be first team coach, or back to his previous role. He's been an integral part of our academy for years and part of our 'DNA'. He knows our youth players better than even DM did, and is the link between the academy and first team.
Back on topic, I think we will 99% go down the temporary boss route and reassess in the summer dependant on what league we are in. The major issue is as others have said, if the temporary boss gets us promoted, how do you not give them a chance in the premier league...