I got one of those 7 day pill compartment things from the $3 Shop. Put the right amount of food in each and ask your parents to feed once a week would be enough. That way the fish will not be overfed, they won't starve, you won't overwork the filter, and the tank should get by without any water changes due to the lower bioload (although if your parents are willing to do a water change or two it would help). Also there should be no need to scrub down the inside of the tank as the fish will have grazed on it, keeping it sparkling clean.
I always clean my filter at least 2 days before I go away. This allows time to see that everything has settled back down well and the filter is continuing to work correctly (sometimes they don't after you have restarted them). I do a good substrate clean too.
Fish do not need light but plants do. Easiest to get a timer to switch on to give the plants 8 hours daily. Dying plants, or removing the plants, will have a bigger, negative effect on the tank than putting the lights on a timer.
Cut back on the feeding before you go, rather than feed them more. This way they will be used to lesser amounts and won't mind the sudden cutback so much. If you feed daily, cut back to every 2nd day then on weekends leave them 3 days without feeding.