Kich, I believe both the ACHA the rosters for D1 and D2 have to be set by the 31st. Now, if the MACHA follows ACHA (which technically is the governing body -- like the NCAA rule book is the governing body of the ACHA -- with some exceptions) then regardless if both teams are D2, the roster must be set prior to playoffs -- Jan. 31st.
Now, if MACHA has that exception to the ACHA in its rules, then yes, teams can move players for playoffs, but I don't think that's the case.