Ok, so good financial situation with low expenses. That's typically a nice factor for RRSP use.
I would agree that the real question is bigger CCB with RRSP contributions vs. fill the TFSA. This is where you should use the CCB payment calculator. If you fill your TFSA, that money compounds every year. For example, filling both TFSAs now and contributing $11,000 per year for 20 years at 5% return would result in a total TFSA value of $650,000 with $325,000 of that amount being investment returns.
On the other hand, if you defer the TFSAs, fill your RRSPs and reinvest the CCB for kids education, your RRSP will grow to $1.6M in 20 years. (Assuming you contribute 18% of $76,000 annually going forward). That's getting pretty big and could result in withdrawals that are twice your annual spending once you turn 71.
I know this isn't a clear answer to your situation, but it gives you an idea of how to do some of the math. It's probably best to plot the RRSP contributions (and bigger CCB) going forward 12 years to when you get cut off CCB. Then factor in continued RRSP growth with less contributions or a more conservative return estimate. Then calculate your taxes and possible mandatory withdrawals when you retire.
Then calculate the potential TFSA value if you maximize that now vs. filling that in 12 years. Figure out the difference that would make to your TFSA value when you retire and start drawing down your portfolio (maybe in your early 60s). Remember, TFSA withdrawals are tax free and could set you up for seniors benefits later (OAS, GIS, pharmacare, etc.)
Then add any business value and how that could realistically impact your portfolio in retirement.
If the CCB benefit outweighs those future taxes, definitely go with RRSP. If it's close, maybe split the difference. If it's not close, go with TFSA now.
You might want to get a good fee-only financial planner on board to help with this as well. They could provide a lot of value when it comes to taxes, business sale to investment portfolio transitions, and other financial stuff. They might also have a better understanding of your personal finance situation than a typical small business accountant.