Unfortunately, No, you can't keep a Pistol Shrimp in a 2g tank, as they will do better with a Goby to tag along with. Kinda like a Clown and a Anemone, they don't need each other but do better with each other. Also, depending on which Pistol Shrimp you get, they do get some size to them also. 10g minimum is what I would suggest.
You also do not need strong lighting is your just going with a Fish Only Tank. A Reef or Mixed Reef is a different story. Again, here I'd not go anything less than 10g.
Here is the Salt Water Check List:
#1-Dry Rock, there are a few hitchhikers on Live Rock that people want to stay away from, so they opt for using Dry Rock, or Dead Rock. Macro Rock is a good place to start looking for that. Either way you go you will need a minimum of 1lb per gallon.
#2-Replacement filter media like filter floss and activated carbon (if you get a filter) Which is really not necessary.
#3-Multiple Power heads (2 or 3) 10x your water volume for just a Fish Only With Live Rock, and at least 20x your water volume for a Reef Tank. So lets say your going reef, and you have a 100g tank, you would need flow in that tank at minimum of 2000gph, or 2 1000gph power heads.
#4-Protein Skimmer, rated at 2 times your water volume. Unless your tank is under 30g, in which case you can do 10% water changes a week to rid the system of detrius. But, you'll have to watch the water parameters close, if things go haywire, you'll have to do more water changes.
#5-Saltwater Test Kits. Reef Test Kit. Test for Ammonia, Nitrites, Nitrates, PH, Phosphates, Calcium, ALK and Magnesium.
#6-Saltwater fish food. Mysis Shrimp, Squid, Cyclopease, Algae Sheets, Romaine . Flake food is not really a good food to feed your marine fish.
#7-Aquarium vacuum. This one is iffy. Most don't use one, if you have enough flow in the tank you won’t need one
#8-Rubber kitchen gloves
#10-Two, clean, never used before, 5-gallon buckets
#11-Aquarium thermometer, digital being the best.
#12-Brush with plastic bristles (old tooth brush) - needed for cleaning the live rock if you don't get Fully Cured Live Rock.
#13-Power Strip, possibly GFCI outlets by the tank.
#14-Optional but definitely recommend getting a Reverse Osmosis or RO/Deionization filter for the make-up water, and a barrel for storing the water.
#15-Possibly a Quarantine Tank for your new fish. They sit in here for a few weeks to kill off parasites and bacteria, to keep it from getting in your main tank
#16-Heater rated for your size tank.
#17-Saltwater Mix. Marine Salt. Instant Ocean is the cheap Salt that beginners and Advanced use alike.
#18-Saltwater Hydrometer or even better a Refractometer, which is more accurate. There is also a Digital Meter that is way advanced if you have the cash.
#19-Aquarium filter (not absolutely necessary if running with adequate amounts of live rock, but nice to have if you need to use a mechanical filter or activated carbon, or GFO and such)
#20-Aquarium substrate such as live sand or crushed coral. Some go bare Bottom, others choose the 2-3" bottom, others, more advanced will try the Deep Sand Bed, which is over 6" deep. Volusion Demo Store Aquarium Nitrogen Cycle and cycling. Methods for ammonia, nitrite removal. aquarium heater in Aquarium & Fish | eBay power heads in Pumps | eBay NEW 0-10% Salinity Refractometer Salt Water Aquarium | eBay MarcoRocks Aquarium Products Bulk Dry Live Rock & Live Sand - Bulk Reef Supply Live Rock and Live Sand: Live Saltwater Aquarium Rock and Sand Fish & Aquarium Supplies: Marine Substrates, Sand, Crushed Coral, Live Sand Aquarium Lighting; Reef, Planted Light Information. PAR, Bulb, Watt, Kelvin, Nanometers, MH, LED. http://live-plants.com/ What Your Coral Needs | Successful Reef Keeping t-5 lighting in Pet Supplies | eBay cree led aquarium in Lighting | eBay Aquarium Salt Mix: Salt for Saltwater and Freshwater Fish Aquariums