The Van Horne LRT is really not a necessity in my opinion. *Also, I think that it has to be either the blue line extension or the Cote-St-Luc LRT.
I would definitely vote for the LRT on CDN and CSL. I would even extend it to run on René Lévesque, merge it with Notre-Dame and make it go up on Pie-IX instead of the rapid bus system they're implanting.*
1st priority to the extension of the blue line towards the east and extension of the orange line to Bois-Franc.
2nd priority to the LRT from CDN-CSL to Pie-IX.
3rd priority (waaaaaay down the list) : LRT on Cavendish and Parc.
4th priority (in dreamland) LRT on Van Horne and blue line extension towards the west.