Moving from EIRL to auto entrepreneur

I’ve been running for 2 years as an EIRL with my husband as conjoint collaborateur. As we move towards retirement I want to slim down our activities and my son in the UK, who worked with the business previously for many years, is taking over running many aspects while I concentrate on more of the services and online elements. This means that the income of the business will be much reduced and the current regime won’t be a good fit any longer. I’m currently registered for TVA, but won’t be anywhere near the threshold and I have a very expensive contract with an accountant as so far the accounts have been relatively complex, but again this won’t be the case any longer.

1 - I’m thinking December would be a good time to switch so I’m set up as a micro entrepreneur from January but wanted to check how long the process takes. And also how do I go about making the switch?

2 - My supplementary questions are about tax—as a new business I’ve had ACRE applied. Will there be any problems caused to this be switching regime?
3 - Similarly, I’m in a rural development area so have had a tax exemption so far. I understand that this would have to be paid back if I moved house but don’t know what the situation is if I change regime.
4 - And finally, what will be my husband’s position if I switch to being a micro entrepreneur? We moved to France before Brexit and are both in the health system. With the smaller business there is no need for him to be a conjoint collaborateur but he has no income (I have a pension from a previous job plus what I earn from the business) so would he still be included in the system?
Many thanks!