I am looking to add a Freezerless refrigerator to my garage which already has an upright freezer. I would like to plug it into the same GFI outlet. Is this too much for one outlet to handle? Should these be "stand-alone"?

What you have to look at is what amp pull each of the units need, and what amp your line and breaker is. But just gut feeling says it would be too much

If your house is not too old, the garage circuit usually is 20 amp. Check the breaker. If these are both new, average size appliances, or at least only a couple of years old, they should be OK on the same outlet unless one starts hard. Rarely will they both start at the same time, but if they do and your voltage droops, you could be tripping breakers and throwing out a bunch of food. Not worth it.

The reason it is recommended that each has it's own circuit is that a compressor motor on startup uses much more current than it's steady running current. If you look at the compressor specification plate you might find a label that says LRA followed by a number. That stands for Locked Rotor Amps and is what the compressor will draw on startup. My DVM has a record feature and I can measure that current (it is too short duration to see on the display). If you know what you are doing, is one way to help decide on whether to condemn a unit or not. If the measured LRA is much higher than the label, the motor is often on it's last legs.