There are pros and cons with each way.
Pros
It depends on the X/Y dimensions are on your 7" figure and how many can fit on a build plate at the same time, but you should be able to print at least 4 per go.
With a printer, you can print the object in several colours without having to worry about mixing dyes, so you may be able to charge more for "special" orders.
You don't have to worry about creating 4 or more moulds. Print as you need.
A well engineered and finished master, can create multiple moulds. If a mould gets damaged, you can always make another.
Generally mixing two part resins is less troublesome and there is little cleanup with a one part mould once it cures.
Casting is generally quick and you'll have results in minutes as opposed to hours.
You don't need power to resin cast something, unless you're using a pressure chamber.
Cons
With moulds, you have to consider mould marks and problems with the moulds if your figure is complex that will require a two or more parts.
Pinholes are a constant nuisance unless you get a vacuum chamber.
Moulds rip and you can only get so many uses out of them.
Photo resins are generally more expensive. Going with cheap resin, is probably going to cause problems removing the supports decreasing the quality of the prints.
You're going to get layer lines with 3d printing. You can decrease the layer height to make it less noticeable, but they still will be there.
3d printing resin is generally more brittle than casting resin. You can go with the PVC like resins (or other flexible types), but that will be more expensive.
With photo resins there is also the cost of nitrile gloves and alcohol, not to mention the risk in dealing with toxic resins.
There are other costs to casting, as you may need gloves, and will need cups to measure out the 2 part resins.
Sorry if the above ideas are not structured in a chart below each way. I just wanted to convey my ideas. I'm sure I missed several pros and cons.
The chances of failed 3d prints and failed castings are about even so I didn't include them in the list, because it all depends on the experience you have and the quality of your tools.
TazMan2000