Good on you for giving this a try! It can be done.
If you can squeeze the space, consider dividing the shed into a flowering area and a veg area. Your veg lights will do double duty and provide heat when the flowering girls are sleeping. Just make sure you aren't inadvertently letting light bleed happen.
If you've got the height, vegging plants below a flowering shelf is a good way to get the most from the heat thrown from your veg light. LST can help control the height. A 24 hour hi/low thermometer or two is a good idea also. Knowing the cold and hot spots and temp differential of inside your shed and the outdoors will help you too. Cardboard or a tarp(s) can be used to create a "micro climate" area inside the shed to hold heat near your plants. Your plants only care what temp they are and could give a fuck if your shed stuff 6 feet away gets cold.
If using veg lights for heat isn't enough, not a bad idea to tape over any lights on an electrical heater that your flowering plants will "see" when they're sleeping, again, you don't want light bleed.
Don't skimp on extension cords, heavy duty is safer. Not a bad idea to get some mouse traps either, the fuckers will chew cords, plants etc.