First, what you describe as a separation agreement is worthless. You don't have a copy signed by him? No lawyers were involved? It's junk.
Next, 90% of questions you would ask a lawyer you can look up the answers to here and save yourself money. For example:
I need to know what i am entitled to in regards to support (50/50 arrangement) RRSP's that I left at the time of separation (2009) I signed off on the house... but got no property. I need to knwo what is considered section 7 exactly etc...
With a 50-50 custody arrangement, you are entitled to offset child support. Search that term here for lots of details.
You are entitled to half the RRSPs you had at the time of separation (minus any pre-marriage value). Did you get more than half in exchange for signing off on the house? Why would you get no property in exchange for that??
Section 7 extraordinary expenses are those that go beyond normal expenses that arise for children. Daycare fees, overnight school trips, private school fees, university tuition, that sort of thing.
Renting a flute so your child can play in the school band? Normal expense for most families. Buying a fancy violin because your musically gifted child is taking private lessons? Extraordinary. Small fee for a day school trip for the class to go to a museum? Ordinary. Thousand dollar fee for the senior trip to Italy? Extraordinary. The dividing line is often based on household incomes, so what may be ordinary for one child's families is extraordinary for another. That's all a lawyer can tell you.
So do your research here first. Then take what we can't answer to your lawyer consultation.
The questions you SHOULD be asking are more philosophical and ethical in nature. Does this lawyer do court? What's his success rate? Does she have experience with cases/situations like yours? Does he believe in shared parenting, or that the mother should have the children? How fast can she get back to you if you phone with a question? What is his hourly rate? Will he waste your time and money sending endless letters back and forth between your ex's lawyer? Look her up on Canlii to see how she did in previous cases and ask him about them. Look him up on Rate my Lawyer to see if past clients had anything to say about him.
Use this site for your research and questions, and use your consultation to determine if this lawyer is a good fit for you and your case. It's like a job interview and you are deciding if you want to hire him or not. Go in with a good idea of where you want to take your case and what result you ultimately hope for, based on realistic research on this forum, and see what he think he can do to get you there.