Okay, What you are asking for is quite simple,
Go to Panel Preferences by right clicking on the taskbar, Panel < Panel Preferences. Then you can go to items and arrange the items the way you want by using the up and down arrow. This should solve your problem for :-
For Battery Percentage, Double Click on Power manager Plugin and select the percentage label in the pop up that appears.
I actually did not understand it, either. In hindsight, your wording seems quite clear.
I think the reason it was harder to understand is that what you are asking for is a bit unusual.
You see, on the panel, the plugins are aligned to discrete blocks. That is hardcoded into the shell.
You are seeking to reorganize and resize those blocks.
I am sorry, but there is no shell extension that can perform that action.
In order to have two unrelated plugins aligned, on a vertical panel no-less... in the space of one block, you would need to resize one block by 1/2. Then realign the other block. Then nest the reduced block within the aligned portion of the other block.
Doing this with Wifi and sound would be near impossible, as the scalable icon sizing would be thrown off and if you moved a plugin location, your gnome-shell would crash.
But doing this with the battery percentage becomes worse, since the percentage value changes size. In one normal sized padded block, that is fine but in the restricted 1/2 size block, fine turns into a nightmare.
I agree with your assessment that it is not possible. Aside from that you would need to adjust, then recompile the gnome-shell from source just to get to the nightmare stage in the first place.
It is an interesting thing since it could also allow for exploring alternative ideas that may introduce you to something new. Like using conky for some actions or in a way you had not considered before.
On thing I have done on XFCE is create a new panel, size it as a large Square, and position it upper left. Then planted a custom Plugin into it with HUD that I could reference, thus using the panel for a purpose entirely different from which it was designed. I also rendered the panel background transparent.
This was a second "panel" on the desktop, with the standard panel in use at the bottom.
So even if you find a door jammed shut, you may look around to find doors you didn't know were there.