It's getting late and I'm not focusing well, but a few comments......
"Do they still have scenic railway trips that go through the Alberta-BC area?"
They do but AFAIK, Via Rail has suspended The Canadian (which travels between Vancouver and Toronto) for several months. I'm not sure when service will resume? There is also a scenic train that travels between Vancouver and Edmonton with a stop in Jasper, which would allow you to visit your friend and still enjoy some beautiful scenery.
*" I would skip Okanagan - its called the "fruit basket" of BC so lots of fruit stands and wineries but not much other touristing."
That's not entirely true! I live in the Okanagan and it has a lot to offer besides wineries and fruit stands. There are a number of world class golf courses (including one that hosted some major golf tournaments), hiking and mountain biking at Silver Star Ski Resort and other locations, boating, summer concerts, mountain biking on the old Kettle Valley railway line or the Okanagan Rail Trail, etc.
In the Vancouver area, in addition to the usual sites such as the Capilano Suspension Bridge, Grouse Mountain or Museums, this is only a short distance from the city - https://www.seatoskygondola.com/ .
As others have suggested, Vancouver is not a good place to have a car as traffic can be a nightmare at times and parking is expensive. As I recall, I was paying at least $30 a day for hotel parking on my last visit. That may change as hotels try to entice customers back.
During your stay in Victoria, in addition to Butchart Gardens there's also the Royal B.C. Museum, which is right downtown. You could also take a whale watching boat trip (although I'm sure you can do that anytime in NS). If you want (and can afford) to splurge on your hotel in Victoria, you might have a look at - https://www.oakbaybeachhotel.com/ . It's very nice!
Of course there's still a lot of uncertainty in terms of what will be operating at that time of year or what restrictions might be in effect.
If renting a car in Alberta and returning in B.C., I'm not sure if there's a supplemental charge. You might want to check on that.
Aside from leaving the dog alone for too long, I'd suggest trying to make the trip as long as possible, as you'll have to deal with two full travel days. I found that it's a full day to travel from here to the east coast (including the time difference). When I was in your part of the world a few years ago, I left here about 10:00 and didn't arrive in Halifax until about 22:00 (one change in Toronto). The flight connections may be worse in the "new reality" but haven't checked that.
As you have a friend in Ladysmith, you might make southern Vancouver Island the main focus and just spend a few days in Vancouver at the end of the trip (without a car). If you're staying at one of the downtown hotels, it's super easy to take the Skytrain Canada Line to the airport for the trip home.
Good luck with your planning!