For blind: Add braille so people could read signs and they can know where to walk and go. Add speakers so they know where they are at the moment and where they need to go to.
For deaf: Add lights and signs to indicate areas and paths.
For mental disability: A service for people who can guide them through the garden. Include peaceful music and sounds so it doesn't affect their mood
For physical disability: Include a wheelchair service for people who can't walk or stand. Include ramps for wheelchair users
For leisure: Include a restraint so they can sit down for some tea and some food to get some energy while they are walking or running around the park