2 - ACARS last transmitted somewhere along the 40 Degree line at 8:11
Not my understanding of the public information. ACARS was shut down shortly after feet wet and before Malaysian ATC bid the flight farewell. Shortly after which the transponder(s) was/were disabled.
The SATCOM system, however, continued to function, in a sort of keep-alive mode, but did not pass flight or aircraft data to the satellite(s). It's the last of those recurring signals that Inmarsat has plotted along roughly the 40N arcs.