There were several proposed start dates for Fall Gelb, but it kept getting pushed back for various reasons. The cancelled invasion dates (according to
this timeline) were Nov 19, 1939; Jan 1, 1940; Jan 17; and May 5, 6, 7, and 8; with the actual invasion occurring on May 9.
The big delay between Jan 17 and the May dates was largely due to having to replace the initial warplan after security was discovered to be compromised. It took several months to write, debate, and approve the new plans, and then to rearrange preparations as required by the new plans.
With a POD of the original plans being compromised earlier, some time in late Summer 1939 (or even if the first leak of the plans in November 1939 was discovered immediately by the Germans), the revised plans might be ready to go into effect in Jan or Feb 1940.
If the war were to go similarly to OTL, that'd mean France would surrender in March or April 1940, which might give Germany enough time to be ready to attack Russia by June or July 1940 (assuming they skip the Battle of Britain and the invasion of the Balkans).
OTL, there was some overlap between the Battle of Norway (April 9 - Jun 10) and the Battle of France (May 10 - June 25), and the Battle of Norway only used a tiny fraction of Heer forces (about 100,000 troops, mostly infantry, in Norway; compared to 3.3 million troops and 3000+ tanks in France). Unless the opening phases of the Battle of Norway required some specific support/logistics resources that was also needed for the Battle of France, I suspect they could probably have happened simultaneously, or overlapping in the other direction (e.g. Battle of France Feb-April, with Battle of Norway as per OTL).