TBBT and this series are now only 7 years apart
In the TBBT storyline, Sheldon and Leonard met four years before the actual show started. Which would make it 2003. Right now, the GMFM Season 2 is in 1996.
This creates a really interesting situation because if they continue GMFM for more than a couple more seasons, then they ought to reference TBBT in some meaningful way.
In addition, Mary from TBBT is only 11 years removed from Mary right now in 1996. They also need to develop her character meaningfully to justify such a change in behaviour in just a few years.
I think the best approach is to acknowledge that this show is no longer in the same canon as TBBT and that these different versions of the same characters, that could give them a lot more creative freedom in terms of Mary, Georgie, etc.