Pets can be great for people who love them and for mental health.
You stated that you asked and everyone agreed it was ok. However, that may not be legally sufficient, especially in the US, especially if you work for a larger organization. People fear retaliation from their manager and coworkers and will go along with the majority under 'duress', then sue later.
I'm going to take the "devil's advocate" position of being against allowing the dog.
I will assume that you work for a larger organization since you stated you 'manage' a 'team'. I will assume that this is a pet:
Some of my contrarian questions are:
- What is the organization's policy?
- If/when the dog bites someone, who is liable? Is the insurance going to cover it? Will the organization indemnify you, even if the bitten person sues you personally?
- What about employees and/or their families who have dog allergies?
- What if it barks, poops, runs around, thus disrupting work?
- If you are in an office building, then the building owners may have a policy about pets.
- Does your manager think it is ok? Did you get that in writing?
- What if the dog has fleas or something?
For the slippery-slope items, which are always present in a group:
- Next person wants to bring in their cat.
- Next person wants to bring in their 3-month or 3-year old human child, because day-care is expensive.
- Next person wants to bring in their great dane, border collie.
And, so on.
If it is your company and your office, then it is your decision, but check your insurance and other legal ramifications.
Satiating one temporary intern is not likely worth the legal risk, unless you already have a pet-friendly policy.
Maybe let them work from home?