Hm, I'm really certain limiting the discussion to that assumption is really the best. I could certainly see the possibility of full-on Anschluss being delayed to after 1934, depending on just how 1931 gets in- after all, if just barely, then France will still be in able to protest Anschluss. Still, Austria being a part of Germany coming earlier is indeed quite likely... though I could see also see a slower, gradual process where Anschluss finishes later, but is less of a break with the past.
Uhm, IMO once the economic union is entrenched the political pressure for full union would soon become irresistible, like it happened for German reunification in 1990. France didn't really played a role in stopping the first Naxi attempt at Anschluss in 1934, it was an Italian job, and I inserted ways in the scenarion for Italy to be bought into acquiescence. Besides, in 1934 France got very close to a fascist coup. It shall have bigger fishes to fry than Grossdeutchsland democratic unification.
Do you think that the enthusiasm for the union could stabilize the Weimar regime?
Or at the very least swing its downfall towards a much saner neo-Kaiserreich right-wing semi-authoritarian regime. Enthusiasm for the coming union would very likely swing some votes away from the Nazis and Commies in the fateful 1932 Reichstag and Parliamentary elections. So that either the democratic parties are able to come up with a parliamentary majority, or Hindenburg and his camarilla throw their weight under Scleichler, not Hitler, for getting and keeping the Chancellorship. Although it may take some serious street violence, we may come up with Scleichler enforcing a constitutional change by coup to expand the executive's powers, change the electoral law, ban the NAzis and Commies, and restore the Kaiser. That would largely stabilize Germany, and the welfare programs and rearmament that brought Germany out of the Great Depression could be done at a less breakneck, sustainable pace. With the Anschluss accomplished by democratic means, Germany would have the leverage to bargain with the powers to return Dnazig and the Sudetenland to Germany by less traumatic means, say a couple of plebiscites. Non-Nazi German nationalists did not have any other strong claims in Europe.
Or we could have a Weimar stabilization. I use mainly the chance of a Schleichler takeover and Kaiserreich restoration because I'm more familiar with the PoD.