There's parts and pieces that will have to be modified. I believe the Bayview Towers is one such example, another section is the choke-point at the HWY 404 underpass where the BRT ROW will be one lane.
Ottawa is going through a similar process right now. With the central portion of the Transitway being converted into LRT, you can definitely see the newer Transitway extensions (opened in the past 10 years or less) were built to be LRT-ready with almost no upgrades needed. The section in Barrhaven from Fallowfield to Barrhaven Centre specifically comes to mind. The central Transitway needs a few more upgrades because the LRT standards weren't as defined in the 70s/80s as they are now.
A lot of what YR is building now has a very similar feel to what Ottawa built in Barrhaven, albeit with a slightly different configuration.