Welcome to the Forum.
1) Lights: I run mine 10hrs/ day
2) Large fish kept in small tanks often don't even reach adult hood, dep how much smaller you're talking about there it may be pretty unhealthy for the fish to live that way. Its sorta like if I raise you in a house with 3ft ceilings, you will grow up yes but since you'll never be able to stand up all your live you will wind up disabled with a cricket back - Know what I mean!?
3) I either feed all my veggies raw or blanched, thou I'd have to say the one's fed raw seem to attract the fish quicker
4) Planted tanks need to simply be in balance with the available CO2 (fish), the nutritions (source water and fish poop etc) and your lights. Most planted tanks fail by inadequate lights (too high wattage to low Kelvin). If you look here to the left under my name, you'll see a tap called "Aquiarium" under which you see all my tanks; apart from a normal filter and fish there's nothing added to these tanks, no ferts, no CO2 nadda...I'd wanna say the plants speak for themselves on the pictures