First Registration How to fill Panel 16 and Panel 17

Background - Deceased aunt's property is unregistered and in the will it falls to her 2 brothers. Brothers do not have capacity so I am making the first registration application. I have power of attorney for one of the brothers. How should I fill in Panel 16 and Panel 17?
I have answered "I am not a conveyancer" in panel 14.
Panel 16 (1): Presumably this is left blank. Panel 16(2) Presumably check the first box.
Which evidence of identity is now needed? AP1, FR1 (i'm already doing that one?), DS2 ??
Panel 17: What do I do now for the signatures of the brothers? They do not have capacity but each has a power of attorney.
Mat

Mat - the late Aunt's executor is the one who will need to transfer the legal ownership
Form FR1 is the application then used to submit the application to register for the first time
Panel 16 is completed with each name so both brothers and yourself as attorney
You then need to provide evidence of identity as per PG 67 section 4
Panel 17 would be signed by you as the attorney if the brothers don;t have capacity.
Form AP1 is not needed as that's an application form used for registered land. And form DS2 is used for applying to discharge a legal charge so also not needed
Whilst you don;t have to use a conveyancer I would always recommend to anyone trying to do this themselves to think about using one. They are familiar with the forms, process and deeds, can verify your identities and also advise on the options available re the legal ownership and more.