My opinions follow:
Is there any benefit to switching over to an independent >investment firm over a bank (given we are not playing around >with tremendous amounts of money).
Not really. Both will try to sell you high cost actively managed mutual funds. I view it a bit like trying to decide between eating dog shit or cat shit, pardon the language.
Given how relatively simple our financial situation is should I just >suck it up and go with a robo advisor (I've read the various >threads re: some people's issues with Wealthsimple and others).
For a hands off approach a robo advisor might be a good choice. I don't have experience with them personally, but their cost will be about half or less of an actively managed mutual fund. You could also consider a low cost balanced mutual fund.
You might also view this as an opportunity to learn about DIY. But I recognize that route isn't for everyone.
Is there anything we're just glaringly doing wrong in all of this? >My biggest worry is that with us moving home, buying a house, >having a baby, and then making some sort of drastic financial >switch (either to a robo advisor or this independent firm) that I'll >choose the wrong thing and screw our burgeoning family over >financially.
It sounds like you have a lot happening all at once. I guess I'd just recommend that you go slow. Kids don't really need much space when they are small. And they don't care what kind of car you drive.