I am an ongoing caregiver. Children seats? I dealt with those when the kids were tots. Dogs? I have seat belt harnesses for mine. I would the carry the harnesses in the trunk or under front seat.
My husband is a double amputee below the knee. I know how to transfer someone between wheelchair & car seat. If cost was not prohibitive, I would love to have access to a van that accommodates wheelchairs.
There are many disabled who do fine alone. Those are the ones who do not allow their disability to be a handicap.