[Alon]

Not only is all of this feasible, but going then from Arbutus to UBC is good for operating costs, because not only does this allow truly eliminating the 99-B, but also it makes travel demand more symmetric. If you just build to Arbutus, you're serving Fairview and the dense residential parts of Kits, and this means that the travel you're going to generate is work trips to Central Broadway and diagonal trips to Downtown. This means westbound trains start to empty out at Cambie. It's only 3 stops after that (and 2 of them are still Central Broadway), but probably you'll still be duplicating the 99-B because otherwise it would require two transfers to get to the Canada Line.

In contrast, if you build to UBC, you're going to start seeing true reverse-peak traffic: a lot of westbound traffic in the morning, and even diagonal trips from Downtown (and the West End, etc.) to UBC.