There were different levels of canon, and they were never 100% canon. But they were in the second level. They're not anything anymore.
Since I value some part of the EU far more than the original story, including these books, it's the movies that aren't canon anymore to me, I'm full former-EU and don't care anymore for the official ones (haven't even seen VII, VIII and Rogue one, and définitively don't intend to, but I've reread a good third of the EU since)
Ysalamiri and Luuke are awful ideas.
Most (all) clone plots are awful, including the canon ones. Except maybe Boba Fett and C'Baoth to some extend.
The Ysalamiri/Vornskr ecology, on the other hand, get a pass to me. It's definitively not a stupid creation and offers a lot of opportunities. But I admit I love SW EU, but I am not fond of Jedis in general (with plently of exceptions).
But there's more valuable and interesting characters created by Zahn and a couple others in the EU than in the canon.