Stoked when I see a post like this! Been a project of mine for quite some time and I'm close to an attempt!
I have been out on the Comino-Waring Ledge a couple of times, first traversing to the far side. It's extremely exposed, and my heart was in my mouth the whole way there and back, although the traverse alone isn't difficult. Also, I believe the rock quality isn't as bad as others have reported, but still slightly worse than the rest of Mt Barney because of lack of traffic, lichen, sun exposure, etc. There is a safe platform between the rockface and a tree at the far end, from which the climb up begins. The second time I went out, I abseiled from the top and practised the climb on belay. A lot of shrubs got in the way and I found myself relying on vegetation for holds, so it's obviously not something I'd do unprotected as that stuff could give out. The Ledge is definitely achieveable, but presents a logistical challenge for protecting yourself.

- Comino-Waring Ledge, climbing up the far end
An alternative is to take Chockstone Gully up to Short Leaning Ridge, then Leaning Peak. I'm yet to evaluate whether this is a more viable path than the Ledge and its timesink of ropework, assuming you have the endurance to not mind doing a bit more distance and elevation to take the Gully. I believe this is the route Robert Rankin took on his Barney all-peaks day.

- Leaning Peak Chockstone Gully
There is mention of (probably) the first completion of the all-peaks circuit in Robert Rankin's Secrets of the Scenic Rim, pp. 168-169, in 1964 by Alan Frost, Tim Cassidy and Barry Smith. They did the 7 peaks you mentioned, which is rarely seen. I have seen plenty of people complete a 6-peak circuit on Barney and leave out Leaning Peak.
However, in my opinion, the true Barney all-peaks day involves 10 peaks with the inclusion of Barrabool, Burrajum and Gwyala peaks, as they are 1) part of the same geological granophyre massif as the rest, with Mount Barney Creek dividing the Ballow massif from the Barney massif 2) at a similar elevation to the other peaks, with Mount Barney Creek constituting a massive drop in elevation that separates them from the Ballow massif peaks. The far western peaks make doing a Barney all-peaks day into quite an endurance challenge, as they are quite a long detour and sheathed in thick vegetation. The 10 peaks are especially visible from Mt Maroon:

- Barney 10 peaks annotated from Maroon
I haven't found any record of anyone doing the whole 10 within a day, although I wouldn't doubt that it's been done over a few days in the past. I'll have to ask some public groups whether it's actually not been done. As I said at the start, this has been a project of mine for some time and I think I'll get it completed in the next month of two, once I find enough free time to do so.