Yes, on the schedule and make sure each is doing their chores AND helping you and/or siblings with things as well; they have to be trained to consider themselves part of a family unit and think of others; including and especially your special needs child
Just a couple of ideas, survival habits you may have fallen into to make your day easier, but long-term prevents self-direction and imaginative play:
get rid of computer games completely for a while
no tv, except family movie night, or some such thing
do not give them any ideas on what they should do with their free time; they become dependent upon your imagination/brain, instead of using their own (this is where there bowl/chart above comes in handy); I always told mine that boredom was a choice and that if they couldn’t figure out something to do, my choice would be severely labor-intensive and no fun
Do they have time away from each other for quiet time DAILY in their rooms?
No coming out till your alarm goes off; no coming out for anything not already in their room (or chosen to take in there); activity must be a quiet activity (books; playdoh; puzzle; reading; drawing; building blocks; sleeping; velco; cars/trucks/trains, audiobook while playing quietly, etc) My dd didn’t like reading when we first adopted her, so I introdced her to stories via audiobooks, especially Jim Weiss and many other unabridged, dramatic readings (she still remembers her Frog and Toad cds and she’s 15:)
When mine were little, in the summer, we switched our schedule so outdoor time (free or specifically nature-specific) was in the AM and after 5 or 6)
Do they have: a sandbox? slides/swings/monkey bars? bikes? rollerskates/blades? frisbees? garden tools for digging? balls/bats? swords/play guns? sidewalk chalk? are there trees to climb? They need to get WORN-OUT
The more classic children’s lit they are exposed to, the more imagination they will have due to the natural desire to recreate their fav parts
HTH