Hi there. First, I am so sorry for your loss. You will know when the time is right for your new yorkie baby. You are right, they don't replace the ones that have passed on but they do help fill that void left in your heart.
Here is my two cents on boarding at a vet. I have seen behind the scenes at a lot of clinics and hospitals. My advice would be to ask for a tour of the facility. If they refuse then I would not board there much less use them for veterinary services.
The advantages of boarding at your vet would be the obvious of having a person available to you right away if there should be a problem. Even something as small as a bought of diarrhea can be treated right away. And at a veterinary facility, they will be more quick to identify a problem.
The disadvantage would be that if the facility is so busy with the goings-on; with their patients, surgeries, hospitalized patients and clients, that boarders often get left on the back burner and may not get walked or checked on until it's time to feed them. This is more common for vet facilities that are really not set up for boarding. The last place I worked at was very much like that. We would get so busy there was nobody available to walk the boarders. Some pets would stay in their kennels all day
. The patients took priority. I always felt bad for the boarders who, at times, were fed and that's all the attention they got. (unless there was a problem of course)
There are some vet facilities that are set up for boarding and have staff that does nothing but take care of their boarders. The pets get walked at scheduled times and receive lots of attention and care. This is why I suggested you ask for a tour and ask questions. Don't be afraid to ask how many walks/play time they get. Ask if they have a kennel person that takes care of the boarders only.