...and besides, the monorail has just been renovated, doesn't make sense to make it redundant.
Dont forget that this is a 10 year plan - the movement of the entrance could be planned for 2019/20, when the monorail would probably be starting to look a bit shabby again :) They probably wouldnt move the entrance until the two "future hotels" were finished, and there is no way that they would be done until around the end of the 10 year plan anyway. Forbidden valley isnt the only area that could be used as a new entrance either, looking on google earth.
It would be unusual to see 3 major coasters in the same area. But, If it was a reinvention of a cross valley wooden rollercoaster, and only contained the station, then It would be more do-able :) UgLand could technically be "extended" towards the old coaster corner too, surely?
Dont forget, the ATA announcement only shows "rumoured" inclusions - they're not definite. That said, ATA are usually pretty accurate.