My family will be in MK on a MVMCP ticket (not park ticket) in December. The ADR I snagged is for 3:40 PM. Will they let us in for the ADR since it can be seen on the MDE app? Or will we be able to get checked in to Liberty Tavern as soon as we make it through the gate? I just don’t want to be late and pay the no-show fee.
May be best to simply call guest services and ask Disney that question directly.
I don’t think they will let you in earlier than 4pm on a party ticket. They haven’t announced officially yet what time you can enter, but I think it’s always been 4pm.
I would look for a slightly later ADR. Or be prepared to be late, maybe just let them know you’re “running late”.(which you would be 
).
Anyone can make ADRs for anytime and you don’t need to have a ticket (exception for DURING the parties.) So just showing an ADR in MDE will not make them let you in or else ADRs would be WAY harder to get! You would need a valid day ticket to get in before 4.