Firebase Database Design - firebase

Question

I have a database containing a structure similar to the one shown below. Since I am not allowed to make it public I am using the following keys:
i = {0,1,2,3....}
All a(i) represent single key/value pairings e.g. userName: "awesome"
With the below structure, every time a User wants to create new Stuff these are the steps I currently take
Store images to FIRStorage and retrieve their respective downloadURL
Then I add the Stuff to FIRDatabase. At this point I add all of the info related to a(i) because they're all under a single child; Stuff.UUID, hence I send one huge dictionary consisting of the data.
The issue arises in adding data to the mini-dictionaries. Because they are in different paths, I have to individually make requests to all of them as shown below
I then add location info
Followed by the respective child of timeStamp
The images information is next to be updated
Subscribe the User to respective Stuff.UUID
Lastly add the User.UUID to the members portion of Stuff
Is it possible to reduce steps 3-7?
As a follow up, is it possible to add values into different paths with one call?
PS: Link to what the code of the above demo might look like. Due to confidentiality stuff I am not allowed to post the actual code.
{
"Users":
{
"JglJnGDXcqLq6m844pZ":
{
a(0),
a(1),
a(2),
a(3),
a(4),
a(5),
"Stuff":
{
"fcWpzduhpPn8XR6Zqca": true,
"gfntTr6TkDwZ439jkW8": true
}
}
},
"Stuff":
{
"fcWpzduhpPn8XR6Zqca":
{
a(0),
a(1),
a(2),
a(3),
a(4),
a(5),
a(6),
a(7),
"location":
{
"latitude":"-17.41439",
"longitude":"-5.85170"
},
"timestamp":
{
"created":
{
a(0),
a(1),
a(2),
a(3),
a(4),
a(5),
},
"lastModified":
{
a(0),
a(1),
a(2),
a(3),
a(4),
a(5),
}
},
"images":
{
"B4FaR6wfJAeXqJ29T33":
{
"imageURL": "https://google.com"
}
},
"members":
{
"JglJnGDXcqLq6m844pZ": true,
"DpHAfrqL4eqbR8QNgHg": true
}
}
}
}