They couldn't manage to retain a high quality pedestrian & active travel experience on the existing line even when they had a billion to play with and virtually unlimited time to plan and deliver it.
The most likely scenario is that councillors vote to put the tram down Roseburn path with a meaningless commitment to active travel, knowing that they can later announce it was unexpectedly difficult / expensive / impossible and has to be value engineered out. That staggers the bad news in a way that is less likely to lead to focused protest.