I doubt any single answer here will be decisive.
Let's pass them one by one.
Child limit - Hard to implement world wide, since invariably some countries would protest that it would be detrimental for them to implement such a thing. Countries with a low birth percentage for instance, coupled with a large(r) elderly sector. Besides, Chai Tea has made some valid points in her own post as well.
An annual performance review? - Ooh golly, I wanna be the reviewer
Education, prosperity and rights for women - Education may be hard in itself, but prosperity is almost impossible. The people in poor countries usually stay poor due to corrupt governent, lack of good investment opportunities, wars, famine, etc. Rights for women is a point best reserved for another topic.
MAke everyone a homosexual? Hmm- Better perhaps to make everybody a eunuch. easier
Legalize cannabilism - We'd need a few cookbooks with original human beef recipes in them as well. Otherwise, it's not even worth considering
Development of modern economies - see the crit on prosperity (three above)
Plagues will evolve - I think they will as well, but with the rapid development of medicine, it would probably be countered before it killed too many. Besides, with much more popular awareness about the nature of sickness and the way it spreads, many people will take reasonable to good protective measures, thereby slowing or stalling the spreading of the disease.
Getting of this rock - Aye. But the prospect of a succesful operation of that kind in the foreseeable future may well be a pipe dream.
Bush as population control - Hmm... Wars 'help' significantly of course, since they usually cut a wide path through fertile men and women. But to suggest it as a good population control device? Nope, would never do that.
Actually, I reckon several factors outside of our control will become population checks - A climate change perhaps, caused by global warming and rising water levels (which coincidentally will also create massive floods, forcing the ofttimes highly populated coastal areas of country to become unliveable, forcing the people further inland, which will lead to
wars.
Next to that, diseases will become rife and start spreading, killing many before cures can be found.
The prospect frankly frightens me...