Water supply ??... Big fire mean lots of water... that would be my priority here. Deck gun the original building and maybe a 2-1/2 looped with one guy sitting on it cutting off the fire into the exposures and minimizing the radiant heat. Original fire building is gone - don't concentrate too much on it. You can see the exposure 2 is involved in the roof area that's where I would have committed a majority of my interior attack.
360 walk around for size up. Then concentrate on saving what isn't already burnt up. There's a lot of structure not yet fully involved with smoke coming out of the eaves/attic.
When I watched the entire short video, I was frustrated by the long deployment of the initial line and its placement. Having said this, it might be better to describe what a normal response for a large residence would be for my department. Initial response is (depending upon the area) two engines and an aerial, with a tender and a third engine for a fill site. This type of working structure would also get a mini-pumper/utility for additional manpower. Initial attack is from the tank, with crews going interior as soon as the second engine has established hydrant water or drop tank water from the tender. Aerial does normal truck work including laddering. Typical initial response would be 24 firefighters (6 per apparatus with two chiefs or duty officers and two on the tanker) Later arriving 10 to 12 mins would be the 3rd engine and the utility bringing the total to 34. In this particular problem, two 1 3/4 lines to the breezeway between the initial fire and the main house. This is obviously in the attic space and needs opened up quickly. Judging at the amount of involvement, there is little chance of victim survival, so an indirect application from the exterior into the main heat, would allow suppression through steam following the draft patterns. The initial building looks to be a 200 gpm requirement, Stopping the extension will need two more lines to protect the search crews in the main house. I am concerned about the amount of dark brown smoke, indicating lots of plastic and/or foam insulation. Perhaps even SIP construction depending upon the age of the structure. This is a recipe for back-draft and rapid fire spread. From the looks of the operation, I would doubt this was effectively stopped.