Family owned UK Limited company and micro-entrepreneur

Apologies for the length of the post!

Firstly some background to our situation.

Myself, wife and two of our children, 10 and 12, (we have two other children over 18 living in the UK), started living in France in September 2018.

My wife and I have a UK limited company of which we each own 50%, and we are its only two employees.

We both receive a small salary and dividends from the UK company.

My wife has started the process of registering as a micro-entrepreneur, in the first instance to handle payments for some teaching and proof reading.

My income is from software development services and software licensing. Now that we are living in France the software development is now done in France. I am currently doing work for a single customer, earning about 70k€ in consultancy per year.

Our goals are:
- To become officially recognised French residents, paying taxes into the French tax system.
- Ensure that we are correctly registered so that we can access the French health system.
- Do anything we can to mitigate against the Brexit fall out - which may be impossible at this stage! (I saw in another question mention applying for a Titre de Séjour).

Currently I’m assuming that:
1. I would register as a micro-entrepreneur (I assume profession libérale is the correct type)
2. There would not be a problem with both my wife and me independently being micro-entrepreneurs
3. Both myself and my wife would have to stop being employees of our UK company
4. As my UK customer and any future UK customers would be invoiced from the UK company I assume that as a micro entrepreneur I will invoice our UK company
5. For any other customers I would invoice direct (from the micro entrepreneur)
6. I would need to find additional customers as I currently only have one (at least another 1 or 2)
7. We could continue to receive a dividend from the UK company
8. Dividends could be taxed in the UK and would not be double taxed in France
9. Dividends although not taxed in France would need to be declared
10. Dividends paid from the UK company are separate from our respective micro-entrepreneur earnings

Finally to the questions!:
1. Are all of my assumptions correct?
2. Based on the description of my situation is becoming micro-entrepreneur the best, most tax efficient business entity to set up as opposed to say a SASU?
3. What are the earnings limits for a micro-entrepreneur?
4. Given I only have one customer how quickly do I need to get more customers as this may take some time?
5. At what point do I actually need to register as a micro-entrepreneur and are my earning only taxed from this point. i.e. although I would like to have everything done before the 29th March, do I only need to start my micro-entrepreneur by 183 days into 2019 and then, would I only be taxed (in the French system) for earnings from this point.
6. By becoming a micro-entrepreneur do I automatically get a Carte Vitale, does this then give myself, wife and children access to the French health system?
7. If my wife say earns 5k€ and I earn 70k€ in 2019, given two children under 18, how do I calculate our total tax bill (I’m excluding any dividends taxed in the UK, if that is the correct thing to do)?
8. We have a personal bank account, do we need a business bank account and do we need to have one each?

Thanks for your help