Japan Permanent Resident-Living out of Japan

Dear Experts,

I am a Japan Permanent Resident, I have been asked by my company to work in the US branch, I am not sure how long would that be (could be around 4-5 yrs as well)
I would like to know any impact due to my non presence in Japan, Specifically below points

1) I understand PR is not revoked/expired unless the re-entry permit or Zairyu care expires. Would there any issue even if I make sure these are not expired
2) Would I have to file taxes in Japan even while I file in the US?
3) I would have to submit my insurance card back to company, Do I need to enroll to any other national insurance in Japan (I would have US insurance)
4) I understand US & Japan has treaty for pension, Do I need to any precaution for nenkin? Like inform my blue book number to any authorities
5) Should I inform the ward office of my departure? Any precautions to be taken? Do I need to maintain any other address in Japan?
6) Do I need to inform immigration about this?

Any other points that you experts think should be taken care would be much appreciated.

1) Get a re-entry permit (will be 5 years for you)
2) reenter Japan to renew zairyu card and re-entry permit if/when required
3) Do the moving out procedure at ward office to delete your juminhyo and tell them that you will be living abroad.
4) You must settle your resident taxes for rest of that year. e.g. if you leave on Jan 1, you might have pay for the whole year.
5)Register with tax office as living abroad. Should be able to do a tax return at that time to settle tax affairs can get back withheld taxes. If you've been resident in Japan for tax purposes for 2 years or more, you may be exempt from US income tax for 2 years.
6) If you don;'t register as abroad for tax purposes you will continue to be liable for health insurance and pension, and back payments would be charged when you re-enter the system. You could continue to pay pension if you wanted to and maintain social national health insurance (but the insurance would be pretty worthless base on the levels of medical cost in US).

Ideally maintain an address in Japan if you want to keep Japanese bank accounts/credit cards/etc active.