Well, since you are in TN status (correct?) that is going to have to end, otherwise you will never get your I-485 submitted NOR approved, as it will be abandoned when you cross the border. To adjust status, you need to be in US for a lengthy period (first the waiting period to file, and then to wait for Advanced parole I-131 approval-- so at least 4-5 moths).
And your spouse needs a visa (either B2 or TN).
You might want to look into commuter green card route instead. Otherwise, you need to be thinking more seriously about having your family move to US at least semi-permanently, which is the purpose of GC after all.