Flora 4 Fauna
Found on Facebook, Flora 4 Fauna often share FREE Guided Botanical Information Walks through Botanical Gardens and the like.
They also Share FREE Information Events, that host Plant sales, such as 'Fire Retardant australian Native Plants'
While I haven't personally attended any of these sessions yet, from the information provided, they almost all the boxes. I am unaware if they are fully inclusive to disabilities as they host events at many different locations around South East queensland.
https://www.facebook.com/Flora4FaunaQLD/