RESP -- The money will only be in there for up to 20years, so VBAL is fine. The incremental gains by optimizing your accounts take a bit of effort (and can have some drag in admin fees) so your time is better spent on optimizing your retirement accounts which have a much longer lifespan.
For informal trust -- I recommend just adding to the RESP, even more than the max for the CESG contribution matching. It all grows tax free, is taxed in kid's names when withdrawn, and can be fully withdrawn pretty much in the first year (two semesters) of them attending post secondary... and many, many FT programs, not just university qualify.
It will save you from opening and managing yet another account, and has tax free growth.
There is a lifetime max of contributions of $50k per child to the RESP (only a portion of this is matched).