@Spain1
You have had some good advice from others on this thread but I wanted to send you, somehow, a little emotional support also.
You sound so overwhelmed with all that has happened and with what needs to be done now. However, as you say yourself, you have a window of opportunity now and, sadly, nothing will change for the better until you change them which you have started to.
Break down the whole scary task, into manageable segments, eg: gathering financial information including those for the new properties he's bought without consultation to you, the house you are living in, the current rental property. Do you have sight of his finances at all? This is all useful information for your solicitor.
Ensure you have strong passwords on your own bank accounts, email account, computer, phone etc so he cannot spy on your actions. Put an action plan together on your computer (I'm assuming you have your own computer which is not linked to other devices he has access to?) with what you need to do so you can tick off each action and also help you focus. Ensure that action plan document has a strong password on it, and give it a boring name.
Don't hesitate to call the police if he becomes violent, and ensure your solicitor knows this is a possibility. Get your solicitor to break down the legal process and timeframes for you in clear terms, not just legalese and ask them questions yourself where things are not clear.
Looking at everything which needs doing can sometimes stop us from even starting, but breaking the task into smaller steps often helps to make things more manageable.
Hold on OP. You are in a tough place but focus on where you want yourself and your children to be in the future. Best wishes. 🌹