Yes, you will need to file her return. Simplest way again using individual not joint prep.
You could file her with Turbotax, using NetFile or on paper.
It is true you need to avoid errors.
Generically, things to watch for:
Make sure you report your own information details including Net Income accurately.
Make sure she does not claim any benefits and credits that you have already claimed.
Make sure she claims any benefits you as a family may be eligible for, but you did not claim.
Here's another approach you might consider. A little more tricky.
Start a new return. Opt for joint preparation. Enter all your info as in the return you filed, and enter your spouse info. Before filing her return, check to see what has changed on your own return by comparing line by line with what has changed.
You can then file only her return.
With your return already filed, you cannot refile it for 2016, but you can make changes. Or you can await CRA reassessing your return, which they may or may not do.