My kids are 11, 6, and 3. I can't really think of much as far as the sibling rivalry. I know sometimes my older two play great and sometimes they're terrible to each other. I always sit them down either individually or together and remind my oldest that she's a lot older than her sister, and remind my younger one that her sister is older and that's why she gets bossy, and just elaborate on that to them. And I'll tell them they are sisters, blah blah blah. I don't know how much it helps, but I have to be firm about it when I talk with them. I also think because they're girls this does work because they're sensitive with me just talking to them (at least for a little while), but if they were boys I don't think talking to them like that would do much. LOL. My next step would be to take away privelages or discipline appropriate things - they're fighting while playing with something then they both get grounded from it. Just stick to your guns with them!
As far as chores... my oldest (11 years) unloads and loads the dishwasher, fills the dog and cat dishes, feeds the fish, changes the cat litter, cleans the bathrooms, and her bedroom. My 6 year old straightens the shoes by the door, takes care of any dishes left in living room and puts throw pillows on couch, and then cleans her bedroom. My 3 year old has to be supervised when doing any cleaning and he doesn't necessarily have daily chores. But I'll be right there with him and give him step by step instructions - "put that on the book shelf, throw that in the toy box, etc." I do give my older two an allowance and the oldest gets a little more than the 6 year old, but she also has more responsibility. You could also do a reward for completing their chores - like they get a happy meal or ice cream at end of week, etc. That may work better for your younger two because even my 6 year old doesn't fully comprehend the money. In fact, I wouldn't give her money/allowance if I didn't have big sister to give one to.
As far as a schedule I only allow each child to pick out one movie or t.v. show each day. Usually around "rest/nap" time. I also limit their computer time - the older two get either 45 min each or an 1 1/2 together - sometimes they play webkinz online together. I also try to incorporate some kind of a craft - draw, color, paint, craft (I'll sometimes pick stuff up for craft), etc. And they have to go outdoors at least once a day (weather permitting). This could be to a park, ride bikes around the neighborhood, just play in own yard, get out the hose if it's real hot out, etc. Of course all this varies depending on what is going on, but my main goal is that they're not just watching t.v. all day long.