#1 the nutrient solution is fine for now (with stuff dat camewith garden) shud b fine as they usually supply u with a veggie and bloom so if they gave u that then u shud b more than ok!
not a lot jst mix like indicated on bottle and then jst water every 1-2 weeksuntil it gets bigger then more often, trust me u'll no wen it needs watering(check soil with fingers wen looks a little bit dry then add a bit.
#3not a lot if u get four desk fans on each corner surrounding the plants then that shud do for now unless u get about 20 plants then u might need an extractor unit.
4#hang the 400w about 10-14 inches above ur plants (depends on the temp if u have a air cooled hood then about 12 inches)
#5 simply no!
6# good luk