I've done it both ways, and I have found that the crated dogs do not mind being crated. It's their own little den. Tango really loved his, and so did Brax.
In fact, we got to where we would leave Tango's open, and he'd go in on his own to nap. Unless we went somewhere, then we closed it, and he was fine with that.
A lot of larger dogs just have no idea that they could be too rough with a cat. And, without us there to supervise... I wouldn't leave a 2 yo with an infant unsupervised.
I'm sure that your decision is the best thing for everyone.
Love All Life, Thank You For Posting! :)