Sending sympathy and condolences your way on the passing of your beloved Vela. Our pets leave mighty big pawprints on our hearts, don't they?
Your question caught my attention because this issue arises frequently for most of us in rescue. I don't believe there's just one 'correct' answer, nor are there any wrong answers. Personally, I do continue using my own dogs' belongings on a new dog although it may not be right away. It depends on the kind of bond we had. It doesn't upset me to see most of my pets' things on a new dog although when it's one of my service dogs, I'm sometimes not as ready to see any of those things used with another dog. Our bond is so intense from 15-17 years of never being out of each others' sight that his or her death leaves me raw for a period of time and I just have to put his things away.
Later on, however, It feels good to see a collar being worn by a new dog. Sometimes when I catch a glimpse of it (just a glimpse, since their long hair covers the collar) it immediately evokes memories, usually funny ones. And I use the experience as an opportunity to caution myself against having expectations that the dog wearing my old boy's collar will be just like him.
I read something years ago that addresses your concern that a new dog "would sense that the older may have passed here and not feel as welcomed into our home using Vela's belongings". Your next dog could just as easily sense that she is very special to you, special enough to merit Vela's things as opposed to feeling unwelcome.
The following is a few lines from Coping With the Loss of a dog by playwright Eugene O'Neill. It's written from the dog's perspective, as a letter to his owners, and includes his Last Will. After urging them to have another dog, a Dalmatian like him, and describing what it should be like, he adds:
To him I bequeath my collar and leash and my overcoat and raincoat, made to order in 1929 at Hermes in Paris. He can never wear them with the distinction I did, walking around the Place Vendôme, or later along Park Avenue, all eyes fixed on me in admiration; but again I am sure he will do his utmost not to appear a mere gauche provincial dog.
So you see, you aren't the only one to ever wonder what to do in this situation. I think your best answer will come from what feels right when you look into your heart.