Child arrangements are completely separate to the divorce petition and the financial settlement. If you are petitioning on the grounds of unreasonable behaviour and there is something he objects to, just remove it, it really means nothing in the end. You just want it signed.
Make sure you have your financial settlement signed off before you file the final degree absolute as you remain financially protected until then.
As a SAHM parent with no income and with primary care of the children you will be entitled to more than 50% as your needs are greater in a needs case. Try to get a part time job, this will demonstrate your willingness to work but low earnings potential, and therefore your need for more capital.
Dont forget to include pensions, get these CETV values on these for the Form E.
Child contact is totally separate, and will be ongoing, things change as they get older anyway. For child arrangements keep a diary of what you do, school runs, meals, homework, etc and what he does, if you can demonstrate he does nothing or very little he will not get 50/50.
Dont discuss the children and finances in the same conversation, they are completely separate issues and have all conversations in writing on email. Centre the children's needs in all conversations about contact. Be polite and detached, anything you write can be used in court.
All legal costs will come from the the joint assets in the end, you just need to find a way to cover them in the meantime. The more he forces you to spend on lawyers the less will be left to meet both of your housing needs, and yours and the children's needs are greater than his.
If he is getting family help with costs try to evidence that, as it can be used to demonstrate he has access to family money and therefore less need than you. HTH.