How do we setup as auto-entrepreneur gite manager and plasterer?

Myself and my partner moved to France 3 months ago. He is registered self employed in UK as a plasterer and is looking to continue that work in France as well as some other business activities such as garden maintenance (basic lawn mowing, not design or landscape) and low level house maintenance activities.

My role is as a live-in gite manager for which I receive a small weekly allowance from the owner for cleaning the gite and managing the changeovers. We both live in the main house for free in return for looking after the house and grounds. My intention is to expand the cleaning / housekeeping / gite management side of things. So in summary both of us are looking to setup a business individually as auto-entrepreneurs in France.

1. He is still registered with HMRC in UK and pays national insurance contributions there. You may not know the answer but does he still have to continue paying this if working in France or vice versa?
2. If he still classes his business in the UK as his primary income, would he then register his activities here in France as being a secondary one. I saw reference on here to primary and secondary registration income levels of more or less than 50% of total income per annum but don’t know the pros and cons of either option. He may just decide to cease activity altogether in the UK. Presumably in that scenario he would have to make one of his french activities, e.g. plastering, his primary with the others as secondary?
3. We know that activities such as plastering / gardening etc. are artisanal. From a plastering point of view he has his own business website in UK along with lots of feedback etc. which we would hope would class as experience. I also note that it is preferential to apply via the chambre metier in person / written form as opposed to online
4. Other benefits - I’ve read that registering with the pole emploi then leads to potential benefit of seeking ACCRE. If he registered pole emploi now, would he have to wait 6 months to register as auto-entrepreneur to then benefit from the ability to apply for Accre? Or can he apply to pole emploi now, and then register as auto-entrepreneur at the same time and still benefit from Accre?
5. If we both register as auto-entrepreneur now for our different activities do we name each other in our applications reference health cover?
6. RSA - is it possible to apply for RSA as a newly arrived resident of France whilst we’re trying to set up our new businesses?