Living with ILs: My in laws live with me too as some of you who have visited know. I work so it's not so bad as we don't see each other 100% of the time. Plus my MIL does help out with Baby E so I am pretty grateful. BUT, we do clash sometimes, usually over parenting philosophy. My mum also comes over 3 days a week to help out and hang out with the grandchild so I have to mediate over differences between the styles of parenting between the grandmothers. Still, I grew up with my grandmas living with me so the notion of living with the in laws was not too difficult to stomach.
Lucky thing is that we can all retreat to our own spaces since we have separate halls, bathrooms etc. I can imagine the potential for conflict if we have to share! At the end of the day it's my house and I get to the set the rules. I think that makes all the difference.
Buying property: My 2 cents' worth - if you are buying freehold, just go ahead and buy. There is no way to time the market accurately and if you are buying to stay and not to speculate, it should be fine. Anyway, land is scarce in Singapore so property should go up in the long-term. Anyway, even when prices correct, you will see that the "low" is still higher than the "low" in the previous cycle. So, buy now if you find the right place and have the financing in place.
Schools: My understanding is that living within 1 km is not good enough for the hot schools. You have to couple that with parent volunteering and/or even church connections to be more assured of a place.