Mulhouse, Montbeliard, Freiberg, Karlsruhe, and Heidelberg Christmas Markets

While I cannot comment on the quality of their respective markets, Heidelberg is overall a more interesting place than Karlsruhe. And the cute parts of Montbéliard can be seen in 30 minutes, tops.

Of the southern Alsace markets, which are worth the time/effort to visit and which could be on the pass list. Trying to choose the favorite due to time restraints.

I've only even been to those in Strasbourg and Colmar, both are pretty good!
To be honest ... Christmas Markets do feel "samey" after the first 3 or so, so I'd also make choices according to the attractions in each town!

Freiberg is totally out of your way. About 600 km distance in eastern Germany. But of course it has a wonderful Christmas market and is highly recommended as hub for visiting the Erzgebirge (ore mountains) where the wooden Christmas items are manufactured and which is known as "Christmas county". Well worth the detour, but not doable as day trip from your other cities.

Oh, I guess you refered to Freiburg! Be sure to watch the spelling when entering the city name in your navigation system ;-)

I don't know about the markets, but what Balso says re Heidelberg and Karlsruhe. Freiburg a better, more attractive option for me. I found downtown Mulhouse to be a bit on the grubby side.

All the famous Alsace wine villages would be worth visiting even if they did not have Christmas markets. They are likely to be decked out in a festive way with lights and all that. Whatever are/is the most pratical for you to reach. Colmar will have the largest market. Outside of that, I'd probably choose Riquewihr, then Ribeauville if you have the time.

I LOVED LOVED LOVED the Strasbourg market.