Advice Needed re. Retirement in Norway

I am hoping someone can point me in the right direction for advice regarding retirement plans in Norway.

First up, my wife and I are dual nationals of Australia and the UK. We are in our 60s, financially independent and the reason we want to retire in Norway is because our daughter and grandchildren live here. We have seen a property which we can afford to buy but before signing on the dotted line, we would like some advice.

1. Are there any government departments or legal advice centres that can help with the legal formalities of moving here?

2. Are there taxation issues moving here? In other words, would our pension from Australia be subject to Norwegian taxation?

3. Will Brexit have any impact on our right to remain in Norway?

4. What is the situation regarding medical needs? We have not lived in the UK for many years and do not have the EHIC cards. Would we need to buy private health insurance and, if so, which providers are recommended?

Any advice would be greatly appreciated.

Thanks
John