Nice image David. As of tonight (Jan 2) with the sunshield fully deployed but not yet tensioned JWST was mag 14.5 at a range of 800,000km. When it gets to L2 it will be twice as far away (1.5 million km) so probably around mag 16 although this will strongly depend on the solar aspect angle. That is 4-5 magnitudes brighter than Gaia.
The Ariane upper stage was magnitude 17.4 tonight at 890,000km. At this rate it will drop below mag 20 in early February when its range exceeds 2.5 million km.