If the signing of the power of attorney is witnessed by a prescribed witness (solicitor, barrister , clerk of a local court etc) and they certify they have explained it to you, the power of attorney 'endures' through any period where you loose capacity to understand...

Yes, you can have any number, although more than 2 can become unmanageable. They can be authorised either: 'Jointly' which means they must both sign any document on your behalf. 'Severally' which means that any one can sign - without necessarily having the consent of...

This is a common request but not easy to fully accommodate. Debate rages among lawyers as to how to deal with this. It is possible to put a condition in the Power of Attorney that says something like 'this Power shall only be valid if I am unable to manage my affairs'...