Answer: A. No, CDC does not have regulations.
Strictly speaking, each state has its own VFC regulations. But all 50 states forbid the use of dormitory- or bar-style refrigerators (defined as “a combination refrigerator/freezer unit that is outfitted with one exterior door and an evaporator plate (cooling coil), which is usually located inside an icemaker compartment (freezer) within the refrigerator.” They are more sensitive to room temperature changes and are prone to causing accidental freezing in the refrigerator compartment. They should not even be used for temporary storage.
If you are in the market for a vaccine refrigerator, I would urge you to look at the biologic-grade models. I would not be surprised to see them required for VFC vaccines within the next decade. The downside...the cost. Expect to pay about $1,800 to $8,000 for a model with an electronic thermostat.
On the bright side, you won't have to spend a lot on a stand-alone freezer (the biologic-grade refrigerators lack a freezer.) For $500-$600 you can buy two 1.5-cubic ft models, using the back-up when you need to defrost the first. Most offices will not need more freezer space.
What's in your wallet? You'd better have some cold cash.