Anschluss can be sped up if Germany dedicates 10 spies to "Support Our Party" in Austria right from January 1936. Playing GER, I pump at least 5 points of Leadership (sometimes closer to 10) until I've got 10 domestic spies and another 10+ to dedicate to Austria plus a few more to start in on Czechoslovakia, France, and the Soviet Union. It generally takes a couple of months to clear out the defensive spies in Austria, and then I go 100% offensive. It's possible to trigger Anschluss by the end of summer of 1937. Party popularity is shown in the Espionage screen, but it's Party Organization that will trigger the event, and that's not visible. In fact, boosting Party Organization actually depresses Party Popularity, so what you're seeing isn't all that meaningful.
Next step is Czechoslovakia, which is easy if you've dedicated spies to reducing their National Unity from early in 1936, and you can afford to split the difference between killing off their spies and lowering NU. Once you've cleared out their domestic spies, you probably won't lose more than a handful over the next year or two. Munich doesn't become available until January of 1938 at the earliest, if your Dissent is less than 1 and their NU is low enough, but I've been able to trigger it on January 1, 1938 in a couple of campaigns. First Vienna follows another set time interval afterwards (10 months?), but is possible around late October of 1938. As pointed out, there's a 10% chance that the Czechs won't accept.