Congratulations on legalization! I would second a 4x4 tent, maybe 3x3 if only four plants (the larger the pot, bigger the plant). Gorilla Grow makes top of the line tents, but I’ve seen Vivosun tents do just fine.
For lighting with LEDs, make sure the PPFD chart covers your needs, it should be throwing down at least 500 PPFD for flowering (that’s the minimum for any area), but not too much in the center (I’ve read plants should not get more than 1,200, but never tested that. Someone please correct me if I’m wrong). I would expect to pay from $400-$800 for a good lamp (Samsung LM301H or lm301B LEDs plus 660nm, IR and UV - you’ll learn a lot about light). I hate monopolies, so I use ledgrowlightsdepot.com. Alibaba will get you quality components for about 30-40% less, but there’s risk in warranty and insurance enforcement nor many UL listed lamps. Lighting seems to be on the tech cycle now, so I would expect them to get cheaper and more powerful over time. The quantum bars provide the best distribution of light.
AC Infinity makes excellent exhaust systems. A 6” fan will work for a 4x4 tent - just make sure to match the fan and tent size. They also have a nice controller with screen to manage everything. Attach a carbon filter if needed.
Medium is your choice. Soil is forgiving and a good place to begin. Foxfarm and Nectar for the Gods make good organic soil and nutrients. Careful on nutrient dosing - the recommendations are about 2x what seems needed.
Environment control is very important. Try to keep between 70-77F, it can get cooler but try not to get much warmer. Relative humidity needs to be managed as well: target higher earlier, lower later, so you may need a humidifier and dehumidifier. Also a couple of electric fans to keep the air flowing and a hygrometer to keep track of everything.