Can my landlord/management buy any size fridge they want?

YES they can. The law simply requires that a fridge must be provided. There is no requirement on size. No they are not legally require to replace with the same size you had before. So long as you do have a working fridge they have not broken any laws.

Be happy they replaced it & with a new one. There are far too many landlords out there that refuse to replace appliances & replace with used when they do.

They can buy any size fridge that they want. They are not required to give you the same size as the old one unless the size of the fridge is specified in your lease.

I bet if you look at your rental agreement or lease (assuming you have one or the other) it states what comes in the apartment and one of the things listed is a fridge (but it won't say the size of the fridge) You have a fridge, therefore they have complied with the agreement.

Unless the dimensions of the fridge were specified in the lease OR the exact size of the fridge was a MATERIAL factor (which you would have to prove) in you moving in.....the landlord is not obligated to get your the same size.

Yes. The smaller one will lower the electric bill and takes up less space. As long as they provide you with a working fridge, it can be any size.

Unless it is a mini fridge as opposed to a full size, you are out of luck. Even then they can probably switch the one for the other.

Unless there is some stipulation in your lease about the size of the refrigerator, you are only to be provided one. Unfortunately, this was probably the cheapest, what was on clearance or what have you, and that is what you received.

You never had one before. It always belonged to them. Like any other private property the owner of that property can buy whatever they want. You can not dictate to others what they will or will not purchase.