I checked out wealthsimple but given that I wanted to use Couch Potato, felt the extra fees wasn't worth it and opened a TD Direct Investing account instead. I chose TD based on a lot of recommendations I found online. I will warn you that it ended up being a massive hassle (due to TD staff errors) transferring my money over to TD and when I set up all the auto-transfers, etc, they messed it up continually for 6+ months. I like the e-series but not sure if other banks would be easier. I have heard many other TD horror stories since. Then again, I have had other annoying stuff happen at other banks too so possibly my impatience with the whole matter is the common denominator :) That said, it's all sorted out now and it's been pretty smooth sailing since.
I use TD e-series for my monthly (under $1k) contributions to each account. But for larger amounts (over $1k per fund purchased is my personal rule of thumb), I buy Vanguard funds based on the Couch Potato portfolio. It means that in my RESP, we have 7 funds (4 e-series + 3 Vanguard). Vanguard has a lower MER than the e-series but costs me $10 per purchase. So e-series works for my $300/mo contribution to the RESP fund while I use Vanguard for my lump sum contributions.
I finally caught up on my unused TFSA contribution room last year so just have $5500 to invest (today actually) for this year. I will be catching up on most of our unused RRSP contribution room (today also, hopefully). I think DH will still have a some unused room left but that will have to wait until next year.
As for TFSA vs RRSP, I've read of arguments both ways. I ended up choosing to put a chunk into RRSPs (at least enough to reduce our income tax bill) and dumping the rest in my TFSA. Now I'll keep TFSA maxed and am working on catching up to our RRSPs - I should hopefully max both RRSPs out by next year.
Our finances are completely merged so I worked through this person by person. That said, I chose to start with myself because my DH had many more other investments in his name so I decided it was more prudent for me to have more investments in my name to start off with. So my suggestion would be to protect your wife a bit more by starting with her and then working on yours.