MrsPB, first thing you got to know, RBC got some index funds with lower MER like 0.7% (if I rembember, rbf556 for canadian stock, rbf557 for US stock, rbf559 for international (unfortunatly edged) and rbf563 for bonds. Then, you cut your fees by 50% rigth away with no transaction cost. Those are available on the bank side AND at DI. With your account size, I would not rush to transfer. You are actually better using the "no trading fee" feature of their funds. This would give you the flexibility to contribute regularly, diversify each account through asset allocation, rebalance, etc for free. I would wait ´till there is about 50k$ Per account before to buy ETFs...
I got about the same number of accounts than you and treat them as a whole big portfolio. I also allocate to be tax efficient (see Canadian Couch Potato "put your assets in their places"). As an exemple, both RRSP could be 100% VXC, RESP 100% VAB and TFSA 100% VCN (invert RESP and TFSA if you prefer, depends of your goals). Then, use the index funds for regular contribution and buy ETFs once a year.
Finaly, make sure to max out every other accounts before investing more than 2,500$ per child per year into RESP because this is the max for the grants.