I had to splice the motor into the old harness, the little probe didn't come with the new motor. I figured it was an important part so... Come to think of it, I might have been able to remove the probe's wires from the connector and insert them into the connector on the new harness. Solder and heat shrink should work fine.
I think ya need that probe. But you are done, so who cares how ya did it, it works, it will be several years before you even consider taking it out and doing that solder job on it.
Did ya at least tape the wirenuts?
I never attach any wires together without solder and heat shrink, at least in the DC world. I only use wire nuts on AC. The probe is in there where it was before, just had to use the old harness instead of the new one.