I have made 45mins connections multiple times this year, and made a few 35mins one last year before they changed the MCT.
To answer one of the questions posed - the 787's do tend to park at remote-stands. If you are in J, you should be fine as there will be a separate bus. If you're in Y, and sat towards the front of the aircraft, you should also be fine - but engage with one of the 'Fast Track' staff, and get them to let you through.
M