First one’s easy… Iron Golems are now added to the Animal Protection plugin. This means only players that are members on the same island as you can kill them.
Second one’s been in Bukkit for a while, and seems it got worse with the 1.4.6 update. It’s the bug that makes you fall through your island randomly, especially when getting out of MobArena.
So I’ve finally found a way and written a plugin that will solve this bug. Let me know on the forums if falling through your skyblock still happens.
Last but not least, wheat growth seemed a bit on the slow side. Increased it a bit, so now it should grow about twice as fast as it used to. I’ll still keep an eye on this, and if it seems too fast it will be toned down a notch.