Currently our bathroom light/fan combo is running on one switch. Want to change to two single-pole switches. One to run the fan and one to run the light. There are only one black, one white and a ground coming from the light/fan unit. Is is possible for me to change to two switches? FYI- there is a double box because I changed the box before doing the switches assuming I would be able to do it.
Yes, but you'll need smart devices to do it
In the smart-switch wiring, you also have a controller module up in the fan assemblt. The smart switch and controller both get always-hot and neutral. The controller then outputs switched-hot-fan and switched-hot-light.
The smart switch and controller must be a matched set. You probably won't need a 2-gang box for the smart switch.
Unfortunately, no. You'll need a second hot conductor. In modern bathrooms you typically see a 14/3 with ground cable run up to the light/fan box. You can also run a new 14/2 cable and use that in conjunction with the existing one if it's easier in your case. If it's on a 20 amp breaker you'll need to use 12/2.
The 14/2 cable coming in from the panel is just fine. It's only the cable up to the fan that needs the second hot conductor.