You can enter the US on B2 status (as a tourist) as a Canadian with a Canadian passport (no visa required) if you can persuade them that you are a Canadian resident. Since they will probably be able to see your old TN as well as your pending TN in the system they may question about this. In practice a Canadian provincial driver's license is good evidence of Canadian residency. Have you had a chance to get this?
In other words--the pending new TN is not in and of itself a problem if you are a Canadian resident for the time being. I'm concerned, though, that given that you also previously had a TN and have only recently returned to Canada, you might not be sufficiently re-established in Canada to be considered a Canadian resident. It will depend partly on how tough or lenient the CBP officer you happen to get at the border is.
Might be good if you updated us a bit as to what has happened since your earlier thread. I think nelsona advised you earlier to stay in the US and not to worry about being out of status for a short interval given your other concerns. Did you go back to Canada? Where is your wife right now? Has she had the baby yet?