GT,
I believe MFL History already has the capability to address both of these issues (one somewhat indirectly, the other very directly):
1. Milestones are meant to be a log of all teams hitting "historic" achievements in your league. I think of it like players getting their 3000th hit in baseball. In your league, it sounds like the default milestone level for points in a game of 150 is simply too low (if it's being achieved this often). You can change that to a higher threshold (or hide it altogether) on the Admin/Layout Options/Milestones page.
2. There is also an existing option to change the minimum # of games required to qualify for Career records -- go to the Admin/Layout Options/Career Records page, and you'll be presented with options like 1 season, 1 1/2 season, 2 seasons, etc
Let me know if that is what you need