1) Strange. Will look into and fix.
2) Right now, yes. There are couple of things regarding landfills/waste that could be implemented in the future:
- Add power plants (one of which could burn waste)
- Once city ordinances (just as in SimCity 2000) are added you could enable "Propagate re-cycling and waste sorting" option which could lower waste generation per day by 50% (or so) but cost more money.
3) That decision was deliberate although there don't seem to be any advantages to that right now. Once flats became available there was no reason to build smaller houses any more and I didn't really like that. In the future different housings would affect different social classes which in turn will affect employment (need lower class population to work in the factories etc.). At that point housing demand effect could be evened out or lowered because that will be managed by employment needs and so on. Not sure if you could build a city of just flats... probably.
Thanks for playtesting and excellent feedback! This really helps me.